No. 00-1937 

In the Supreme Court of the United States 

JO ANNE B. BARNHART, 
COMMISSIONER OF SOCIAL SECURITY, PETITIONER 

v. 

CLEVELAND B. WALTON 

ON WRIT OF CERTIORARI 
TO THE UNITED STATES COURT OF APPEALS 
FOR THE FOURTH CIRCUIT 

BRIEF FOR THE PETITIONER 

THEODORE B. OLSON 

Solicitor General 

Counsel of Record 

ROBERT D. MCCALLUM, JR. 

Assistant Attorney General 

EDWIN S. KNEEDLER 

Deputy Solicitor General 

JEFFREY A. LAMKEN 

Assistant to the Solicitor 

General 

JOHN C. HOYLE 
MARK S. DAVIES 

Attorneys 

Department of Justice 
Washington, D.C. 20530-0001 
(202) 514-2217 

QUESTIONS PRESENTED 

Title II and Title XVI of the Social Security Act define 
“disability” as the inability to “engage in any substantial 
gainful activity by reason of any * * * impairment which 
can be expected to result in death or which has lasted or can 
be expected to last for a continuous period of not less than 12 
months.” 42 U.S.C. 423(d)(1)(A); 42 U.S.C. 1382c(a)(3)(A) 
(1994 & Supp. V 1999). Under Title II, once a claimant is en- 
titled to disability benefits, the claimant may engage in sub- 
stantial gainful activity during a “trial work period” of up to 
nine months without that work activity being considered in 
determining whether his disability has ceased. 42 U.S.C. 
422(c). The questions presented are: 

1. Whether a claimant is entitled to disability benefits 
under Titles II or XVI of the Social Security Act if he has a 
physical or mental impairment that has lasted or can be ex- 
pected to last for at least 12 months, but his inability to en- 
gage in substantial gainful activity by reason of that impair- 
ment has not lasted and cannot be expected to last for 12 
months. 

2. Whether a claimant is entitled to disability insurance 
benefits and a “trial work period” under Title II even 
though, at the time his disability benefits claim is adjudi- 
cated, the evidence shows that his impairment no longer pre- 
vents him from performing substantial gainful activity and 
that it did not do so for 12 continuous months. 

(I) 

TABLE OF CONTENTS 

Page 

Opinions below ............................................................................... 
1 

Jurisdiction ...................................................................................... 1 

Statutory provisions involved ..................................................... 

1 

Statement ........................................................................................ 2 

A. Statutory and regulatory framework ......................... 
2 

1. Title II disability insurance program .................... 
2 

2. Title XVI supplemental security income 
program ................................................................... 5 

3. Regulatory implementation .................................... 

5 

a. Disability .............................................................. 
6 

b. Trial work ............................................................. 
8 

B. Proceedings in this case ................................................. 
9 

Summary of argument .................................................................. 
14 

Argument: 

I. The Social Security Act does not provide 

disability benefits to a claimant whose 
impairment has not lasted and cannot be 
expected to last 12 months at a disabling 

level of severity ......................................................... 

19 

A. The Commissioner has reasonably con- 
strued the Act to require that a claimant’s 

inability to engage in substantial gainful 
activity last for 12 months ................................ 
22 

B. The Commissioner’s interpretation is 

supported by the history of Congress’s 
amendments to the Act ................................... 

32 
C. The court of appeals’ construction creates 

precisely the short-term disability pro- 
gram that Congress chose not to enact ......... 39 

(III) 

IV 

TABLE OF CONTENTS—Continued: 
Page 

II. Section 422(c)(2) does not provide a “trial 
work” period where the claimant returns 

to substantial gainful activity within 12 
months of the alleged onset of his disability 
and before being awarded benefits ........................ 

42 

A. Reversal of the court of appeals’ ruling 
concerning the necessary duration of the 
inability to engage in substantial gainful 

activity requires reversal of its ruling on 
the trial work issue ............................................ 

43 
B. In any event, the court of appeals erred 

in its interpretation of 42 U.S.C. 422(c) and 
423(d)(1)(A) ......................................................... 44 

Conclusion ....................................................................................... 50 

TABLE OF AUTHORITIES 

Cases: 

Alexander v. Richardson, 451 F.2d 1185 (10th Cir. 
1971), cert. denied, 407 U.S. 911 (1972) ..................... 
26, 27, 28 

Amax Land Co. v. Quarterman, 181 F.3d 1356 
(D.C. Cir. 1999) ....................................................................... 
31 

Batterton v. Francis, 432 U.S. 416 (1977) ......................... 
22 

Bowen v. Yuckert, 482 U.S. 137 (1987) ........... 
4, 5-6, 11, 22, 38 

Cheney R.R. v. ICC, 902 F.2d 66 (D.C. Cir.), 
cert. denied, 498 U.S. 985 (1990) ......................................... 
31 

Chevron U.S.A. Inc. v. Natural Res. Def. 

Council, Inc., 467 U.S. 837 (1984) ................. 

12, 22, 23, 31, 39 

Cleveland v. Policy Mgmt. Sys. Corp., 526 U.S. 795 
(1999) ........................................................................................ 5 

Commodity Futures Trading Comm’n v. Schor, 
478 U.S. 833 (1986) ................................................................ 

36 

Estep v. Richardson, 459 F.2d 1015 (4th Cir. 
1972) ......................................................................................... 28 

V 

Cases—Continued: Page 

Heckler v. Campbell, 461 U.S. 458 (1983) ......................... 
22 

Leftwich v. Gardner, 377 F.2d 287 (4th Cir. 
1967) ......................................................................................... 4 

Lorillard v. Pons, 434 U.S. 575 (1978) ............................... 

33, 38 

Martini v. Federal Nat’l Mortgage Ass’n, 178 F.3d 
1336 (D.C. Cir. 1999), cert. dismissed, 528 U.S. 1147 
(2000) ........................................................................................ 31 

McDonald v. Bowen, 818 F.2d 559 (7th Cir. 1986) .......... 

28 

Mobile Communications Corp. v. FCC, 77 F.3d 1399 
(D.C. Cir.), cert. denied, 519 U.S. 823 (1996) .................... 
31 

Mourning v. Family Publ’n Serv., Inc., 411 U.S. 
356 (1973) ................................................................................. 
30 

NLRB v. Bell Aerospace Co., 416 U.S. 267 (1974) ........... 
36 

Pauley v. Bethenergy Mines, Inc., 501 U.S. 680 
(1991) ........................................................................................ 30 

Regions Hosp. v. Shalala, 522 U.S. 448 (1998) ................. 

22 

Schweiker v. Gray Panthers, 453 U.S. 34 (1981) ............. 
23 

Sims v. Apfel, 530 U.S. 103 (2000) ...................................... 
6 

Sullivan v. Everhart, 494 U.S. 83 (1990) ........................... 
39 

Sullivan v. Zebley, 493 U.S. 521 (1990) ............................. 
22, 23 

Texas Rural Legal Aid, Inc. v. Legal Servs. Corp., 
940 F.2d 685 (D.C. Cir. 1991) ............................................... 
31 

Titus v. Sullivan, 4 F.3d 590 (8th Cir. 1993) .................... 
28 

Whetsel v. Network Prop. Servs., LLC, 246 

F.3d 897 (7th Cir. 2001) ........................................................ 

31 

Statutes, regulations and rules: 

Employment Opportunities for Disabled Americans 

Act of 1986, Pub. L. No. 99-643, § 4, 100 Stat. 3575 ......... 

5 

Social Security Act, 42 U.S.C. 301 et seq. ............................. 
1 

Tit. II, 42 U.S.C. 401 et seq. ............................................. 
passim 

42 U.S.C. 405(a) ................................................................ 
22, 33 

42 U.S.C. 405(b) ................................................................ 
6 

42 U.S.C. 421(a) ................................................................ 6 

VI 

Statutes, regulations and rules—Continued: 
Page 

42 U.S.C. 421(a)(1) ..................................................... 
6, 25, 33 

42 U.S.C. 421(a)(2) ................................................ 
6, 22, 25, 33 

42 U.S.C. 421(b) ................................................................ 
6 

42 U.S.C. 421(c) ................................................................ 
6 

42 U.S.C. 422 ............................................................. 
17, 44, 48 

42 U.S.C. 422(c) ............................................. 
4, 13, 17, 42, 44 

42 U.S.C. 422(c)(1) ............................................................ 
48 

42 U.S.C. 422(c)(2) ...................................................... 
5, 43, 48 

42 U.S.C. 422(c)(3) ................................... 
5, 8, 13, 18, 43, 46 

42 U.S.C. 422(c)(4) ............................................................ 
43 

42 U.S.C. 422(c)(4)(A) ...................................................... 
5 

42 U.S.C. 422(c)(4)(B) ...................................................... 
5 

42 U.S.C. 423 ..................................................................... 
38, 44 

42 U.S.C. 423(a) ................................................................ 
13 

42 U.S.C. 423(c) ................................................................ 
41 

42 U.S.C. 423(c)(2) (1958) ................................................ 
3, 33 

42 U.S.C 423(c)(3) (1958) ................................................ 
4 

42 U.S.C. 423(c)(2) ............................................................ 
13 

42 U.S.C. 423(c)(2)(A) ................................................ 
4, 40, 41 

42 U.S.C. 423(d) ................................................. 
15, 24, 27, 35 

42 U.S.C. 423(d)(1)(A) ................................................. 
passim 

42 U.S.C. 423(d)(2)(A) ................................................. 
passim 

42 U.S.C. 423(d)(4)(A) (1994 & Supp. V 1999) ............ 
10 

Tit. XVI, 42 U.S.C. 1381 et seq. ...................................... 
passim 

42 U.S.C. 1382c (1994 & Supp. V 1999) ........................ 
5 

42 U.S.C. 1382c(a)(3)(A) (1994 & Supp. V 
1999) .................................................................... 
5, 15, 19, 37 

42 U.S.C. 1382c(a)(3)(B) ....................................... 
5, 15, 19, 37 

42 U.S.C. 1383(d)(1) ......................................................... 
22 

42 U.S.C. 1383b(a) ............................................................ 
6, 22 

Social Security Amendments of 1954, ch. 1206, 68 Stat. 
1052: 
§ 102(b)(2), 68 Stat. 1063 .................................................. 
35 

§ 106: 
68 Stat. 1079 ................................................................. 34 

VII 

Statutes, regulations and rules—Continued: 
Page 

68 Stat. 1080 ................................................................. 
34 

Social Security Amendments of 1956, ch. 836, § 103, 
70 Stat. 815 ........................................................................ 
2, 19, 33 

Social Security Amendments of 1960, Pub. L. 

No. 86-778, 74 Stat. 924 ........................................................ 

2-3, 4 

Social Security Amendments of 1965, Pub. L. 

No. 89-97, § 303(a)(1), 79 Stat. 366 ..................................... 

3, 35 

Social Security Amendments of 1967, Pub. L. No. 
90-248, § 158(b), 81 Stat. 868 ............................................... 
4 

Social Security Amendments of 1972, Pub. L. No. 
92-603, 86 Stat. 1329............................................................... 
4 

§ 301, 86 Stat. 1465 ........................................................... 
5 

Social Security Disability Benefits Reform Act of 
1984, Pub. L. No. 98-460, 98 Stat. 1794 .............................. 
38 

Social Security Independence and Program Improve- 
ments Act of 1994, Pub. L. No. 103-296, § 106(d), 
108 Stat. 1476 .......................................................................... 
2 

20 C.F.R.: 

Pt. 404 ...................................................................................... 

1 

Section 404.929 (2000) ...................................................... 
6 

Section 404.1501(f ) (1960) ................................................ 
6 

Section 404.1502(f ) (1960 Supp.) .................................... 
24 

Section 404.1502(f ) (1961) ................................................ 
6, 24 

Section 404.1520 (1982) .................................................... 
38 

Section 404.1520(b) (2000) ......................................... 
7, 11, 26 

Section 404.1520(f ) (2000) ................................................ 
7, 26 

Section 404.1520(g) (1961) ............................................... 
24 

Section 404.1571 (2000) .................................................... 
7, 26 

Section 404.1574(b)(2) (2000) ........................................... 
10 

Section 404.1574(b)(2) (2001) ........................................... 
10 

Section 404.1574(c) (2001) ................................................ 
27 

Section 404.1575(d) (2001) ............................................... 
27 

Section 404.1592 ................................................................ 
8 

Section 404.1592(d)(2) ....................................................... 9, 44 

VIII 

Rules—Continued: Page 

Pt. 416 ...................................................................................... 
1 

Section 416.920(b) ............................................................. 
11 

Social Security Ruling: 

Rule 73-7c (1973) (Cum. ed. 1971-1975) ................... 

6, 26, 38 

Rule 82-52 (1982) (Cum. ed. 1981-1985) ..... 
9, 10, 26, 38, 44 

Miscellaneous: 

SSA, Concepts of Disability and Principles of 

Evaluation (Jan. 1966) .......................................................... 

25 

SSA Disability Insurance Letter No. II-24 (Pt. II 
of Disability Insurance State Manual) (Aug. 30, 1965) ... 
25 

SSA Disability Insurance Letter No. III-6 (Pt. III of 

Disability Insurance State Manual) (Nov. 19, 1965) ..... 

25, 26 

Disability State Insurance Manual (Sept. 9, 1965) ............. 
25 

22 Fed. Reg. (1957): 

p. 4362 .................................................................................. 

24 

p. 4363 .................................................................................. 
24 

60 Fed. Reg. (1995): 

p. 12,166 ............................................................................... 

7 

p. 12,168 ............................................................................... 
14 

65 Fed. Reg. (2000): 

p. 42,772 ............................................................................... 

7, 20 

p. 42,774 ........................................................ 
7, 8, 20, 27, 45, 47 

p. 42,780 ........................................................ 
7, 8, 18, 27, 45, 49 

p. 42,787 ........................................................................... 
8, 9, 44 

Hearings on H.R. 6675 Before the Senate Comm. on 

Finance, 89th Cong., 1st Sess., Pt. 1 (1965) ...................... 

36, 37 

H.R. Conf. Rep. No. 964, 101st Cong., 2d Sess. 
(1990) ........................................................................................ 48 

H.R. Rep. No. 1698, 83rd Cong., 2d Sess. (1954) ................ 

34 

H.R. Rep. No. 1189, 84th Cong., 1st Sess. (1955) .. 
2, 15, 19, 29, 

33, 39, 41 

IX 

Miscellaneous—Continued: Page 

H.R. Rep. No. 1799, 86th Cong., 2d Sess. (1960) ................. 
3 

H.R. Rep. No. 213, 89th Cong., 1st Sess. (1965) .................. 
35 

H.R. Rep. No. 544, 90th Cong., 1st Sess. (1967) .................. 
4 

H.R. Rep. No. 231, 92d Cong., 1st Sess. (1971) ........ 
4, 20, 38, 42 

H.R. Rep. No. 618, 98th Cong., 1st Sess. (1984) .................. 
38, 39 

OASI Disability Insurance Letter No. 39 (Pt. V of 

Disability Insurance State Manual) (Jan. 22, 1957) ......... 

25 

Performance Plan for Fiscal Year 2002 <http://www. 
ssa.gov/performance/2002/2002perfplan.pdf> ................. 8 

S. Rep. No. 1987, 83d Cong., 2d Sess. (1954) ..................... 

34 

S. Rep. No. 404, 89th Cong., 1st Sess., Pt. I (1965) ........ 
passim 

S. Rep. No. 544, 90th Cong., 1st Sess. 31 (1967) ................. 
37 

S. Rep. No. 744, 90th Cong., 1st Sess. (1967) ........... 
4, 21, 32, 37 

S. Rep. No. 408, 96th Cong., 1st Sess. (1979) ...................... 
36 

Social Security Program Operations Manual (2001) .......... 
7 

The Social Security Amendments of 1954: Hearings 

Before the House Comm. on Ways and Means, 83d 
Cong., 2d Sess. (1954) ............................................................ 35 

In the Supreme Court of the United States 

No. 00-1937 

JO ANNE B. BARNHART, 
COMMISSIONER OF SOCIAL SECURITY, PETITIONER 

v. 
CLEVELAND B. WALTON 

ON WRIT OF CERTIORARI 
TO THE UNITED STATES COURT OF APPEALS 
FOR THE FOURTH CIRCUIT 

BRIEF FOR THE PETITIONER 

OPINIONS BELOW 

The opinion of the court of appeals (Pet. App. 1a-14a) is 
reported at 235 F.3d 184. The opinion and judgment of the 
district court (Pet. App. 15a-26a, 27a) is unreported. 

JURISDICTION 

The judgment of the court of appeals was entered on De- 
cember 18, 2000. A petition for rehearing was denied on 
February 27, 2001 (Pet. App. 62a). On May 21, 2001, the 
Chief Justice extended the time within which to file a peti- 
tion for a writ of certiorari to and including June 27, 2001. 
The petition was filed on June 27, 2001, and was granted on 
September 25, 2001. The jurisdiction of this Court rests on 
28 U.S.C. 1254(1). 

STATUTORY PROVISIONS INVOLVED 

Relevant provisions of the Social Security Act, 42 U.S.C. 
301 et seq., and the relevant regulations, 20 C.F.R. Pts. 404, 
416, are set forth in the Appendix to the petition, Pet. App. 
63a-104a. 

(1) 

2 

STATEMENT 

Title II of the Social Security Act, 42 U.S.C. 401 et seq., 
provides disability insurance benefits to individuals suffering 
from a long-term disability, and Title XVI of the Act, 42 
U.S.C. 1381 et seq., provides for the payment of Supplemen- 
tal Security Income (SSI) to such individuals if they satisfy 
financial need requirements. This case concerns whether the 
Commissioner of Social Security, when determining whether 
a claimant is entitled to disability benefits, may deny the 
claim because the claimant was capable of engaging in—and 
had in fact successfully engaged in—substantial gainful ac- 
tivity within 12 months of when his impairment first pre- 
vented him from performing substantial gainful activity.1 

A. Statutory and Regulatory Framework 

1. Title II Disability Insurance Program. As enacted in 
1935, Title II of the Act provided old-age benefits for cov- 
ered workers who retired at age 65, but made no provision 
for “a lower retirement age for those who are demonstrably 
retired” before age 65 “by reason of a permanent and total 
disability.” H.R. Rep. No. 1189, 84th Cong., 1st Sess. 3 
(1955). Because Congress concluded that covered workers 
“forced into retirement * * * prior to age 65” should also 
receive benefits, id. at 4, Congress amended the Act in 1956 
to establish a system of disability benefits. See Social Secu- 
rity Amendments of 1956, ch. 836, § 103, 70 Stat. 815.2 

1 Until 1995, the social security program was administered under the 
supervision of the Department of Health and Human Services (HHS). In 
1994, Congress established the Social Security Administration as an 
agency independent of HHS and headed by the Commissioner of Social 
Security. See Social Security Independence and Program Improvements 
Act of 1994, Pub. L. No. 103-296, § 106(d), 108 Stat. 1476. References in 
this brief to the Commissioner for periods prior to 1994 are to the Secre- 
tary of HHS, or to his predecessor, the Secretary of Health, Education, 
and Welfare. 

2 The 1956 amendments limited disability benefits to covered em- 
ployees who were at least 50 years of age. In 1960, Congress eliminated 
that restriction. Social Security Amendments of 1960, Pub. L. No. 86-778, 

3 

Under the 1956 amendments, the Act defined “disability” 
as the inability to engage in “any substantial gainful activity” 
by reason of an “impairment which can be expected to result 
in death or to be of long-continued and indefinite duration.” 
42 U.S.C. 423(c)(2) (1958). In 1965, Congress revised that 
definition. “[E]xperience under the disability program” had 
“demonstrated [that] in the great majority of cases in which 
total disability continues for at least a year the disability is 
essentially permanent.” S. Rep. No. 404, 89th Cong., 1st 
Sess., Pt. I, at 99 (1965). Accordingly, Congress replaced the 
“long-continued and indefinite duration” requirement of the 
original definition of “disability” with a 12-month duration 
requirement. See Social Security Amendments of 1965, Pub. 
L. No. 89-97, § 303(a)(1), 79 Stat. 366. Congress concluded 
that the new duration requirement would (like the old one) 
prevent the program from paying “disability benefits in 
cases of short-term, temporary disability.” S. Rep. No. 404, 
supra, at 98. As a result of the 1965 amendments, the Act’s 
basic definition now reads as follows: 

The term “disability” means—inability to engage in any 
substantial gainful activity by reason of any medically 
determinable physical or mental impairment which can 
be expected to result in death or which has lasted or can 
be expected to last for a continuous period of not less 
than 12 months. 

42 U.S.C. 423(d)(1)(A). 

The Act further provides that an individual “shall be de- 
termined to be under a disability only if his physical or men- 
tal impairment or impairments are of such severity that he is 
not only unable to do his previous work but cannot, consid- 
ering his age, education, and work experience, engage in any 

74 Stat. 924. Congress concluded that the “need of younger disabled 
workers * * * for disability protection” may be “greater than that of 
older workers” because younger workers “are more likely to have families 
dependent upon them.” H.R. Rep. No. 1799, 86th Cong., 2d Sess. 12 
(1960). 

4 

other kind of substantial gainful work which exists in the 
national economy.” 42 U.S.C. 423(d)(2)(A) (emphasis added). 
Congress added that provision to the Act in 1967. See Social 
Security Amendments of 1967, Pub. L. No. 90-248, § 158(b), 
81 Stat. 868; Bowen v. Yuckert, 482 U.S. 137, 147-148 (1987). 
The addition responded to a Fourth Circuit decision, Left- 
wich v. Gardner, 377 F.2d 287 (1967), which had held that a 
claimant was under a disability even though he was working 
at a level that, according to the Secretary of Health, Educa- 
tion and Welfare, demonstrated an ability to engage in sub- 
stantial gainful activity. H.R. Rep. No. 544, 90th Cong., 1st 
Sess. 29, 31 (1967). The new provision was found necessary 
“to reaffirm that an individual who does substantial gainful 
work despite an impairment or impairments that otherwise 
might be considered disabling is not disabled.” S. Rep. No. 
744, 90th Cong., 1st Sess. 49 (1967). 

Title II also provides a “waiting period” during which a 
claimant, even if under a disability, is not entitled to disabil- 
ity insurance benefits. The “waiting period” is “the earliest 
period of five consecutive calendar months * * * through- 
out which the individual * * * has been under a disability.” 
42 U.S.C. 423(c)(2)(A). The 1956 amendments had imposed a 
6-month waiting period. See 42 U.S.C. 423(c)(3) (1958). 
Congress reduced the waiting period to 5 months in 1972. 
See Social Security Amendments of 1972, Pub. L. No. 92-603, 
86 Stat. 1329. Reducing the waiting period did not alter the 
severity or duration requirements for a finding of disability. 
As before, “[n]o benefit is payable * * * unless the disabil- 
ity is expected to last (or has lasted) at least 12 consecutive 
months.” H.R. Rep. No. 231, 92d Cong., 1st Sess. 56 (1971). 

Finally, Title II provides a “trial work period” to encour- 
age individuals receiving disability benefits to return to 
work when possible. See 42 U.S.C. 422(c), as added by the 
Social Security Amendments of 1960, Pub. L. No. 86-778, 74 
Stat. 924. During the trial work period, a beneficiary may 
perform substantial gainful activity for up to nine months 

5 

(which need not be consecutive) without losing benefits. The 
“period of trial work” begins “with the month in which [the 
claimant] becomes entitled to disability insurance benefits.” 
42 U.S.C. 422(c)(3). The period ends after the beneficiary 
has performed services for nine months, or in the month in 
which the disability actually ceases, whichever is earlier. 42 
U.S.C. 422(c)(4)(A) and (B). “[A]ny services rendered by an 
individual during a period of trial work” are “deemed not to 
have been rendered by such individual in determining 
whether his disability has ceased in a month during such pe- 
riod.” 42 U.S.C. 422(c)(2); see also Cleveland v. Policy 
Mgmt. Sys. Corp., 526 U.S. 795, 805 (1999). 

2. Title XVI Supplemental Security Income Program. 
Congress enacted Title XVI of the Act in 1972 to provide 
income to financially needy persons who are aged, blind, or 
disabled. See Social Security Amendments of 1972, Pub. L. 
No. 92-603, § 301, 86 Stat. 1465, 42 U.S.C. 1381 et seq. Unlike 
Title II, which is an insurance program, the SSI program is a 
welfare program based on financial need. Yuckert, 482 U.S. 
at 140. The definitions of disability under Title XVI, 42 
U.S.C. 1382c(a)(3)(A) (1994 & Supp. V 1999); 42 U.S.C. 
1382c(a)(3)(B), are essentially identical to those under the Ti- 
tle II disability program, 42 U.S.C. 423(d)(1)(A) and (2)(A). 
The Title XVI SSI program, unlike the Title II disability 
insurance program, does not have a waiting period. Instead, 
benefits are paid to qualifying disabled individuals beginning 
with the first month after the month in which an application 
is filed. The Title XVI SSI program also does not provide a 
“trial work period.” Rather, it offers a number of “work in- 
centives.” See Employment Opportunities for Disabled 
Americans Act of 1986, Pub. L. No. 99-643, § 4, 100 Stat. 3575 
(amending 42 U.S.C. 1382c to eliminate trial work period). 

3. Regulatory Implementation. The Social Security Act 
provides that the initial determination of whether a claimant 
is disabled may be made by a state agency “acting under the 
authority and supervision of ” the Commissioner. Yuckert, 

6 

482 U.S. at 142; see 42 U.S.C. 421(a), 421(c), 1383b(a).3 If the 
state agency determines that the claimant is not disabled, 
the claimant may obtain a formal hearing before an Adminis- 
trative Law Judge (ALJ) in the Social Security Administra- 
tion (SSA), and may obtain review of an adverse decision by 
SSA’s Appeals Council. 42 U.S.C. 405(b); 20 C.F.R. 404.929 
(2000); Sims v. Apfel, 530 U.S. 103, 105 (2000). A state 
agency’s initial determination of disability must be made “in 
accordance with * * * the standards and criteria contained 
in regulations or other written guidelines of the Commis- 
sioner of Social Security.” 42 U.S.C. 421(a)(1) and (2). 

a. Disability. The Commissioner, by regulation and in 
instructions issued to state agencies pursuant to 42 U.S.C. 
421(a)(1), has for more than four decades interpreted the Act 
as precluding an award of disability benefits unless both the 
claimant’s impairment and his inability to engage in substan- 
tial gainful activity by reason of the impairment have lasted 
or can be expected to last for at least 12 consecutive months. 
Thus, it is not enough that an individual’s underlying medical 
impairment has lasted or can be expected to last, at some 
discernible level, for 12 months. Instead, the impairment 
must last or be expected to last at a sufficient level of sever- 
ity to render the individual disabled—i.e., to render him un- 
able to engage in substantial gainful activity—for at least 12 
months. See, e.g., 20 C.F.R. 404.1501(f ) (1960) (duration re- 
quirement not met if, within the foreseeable future, “the im- 
pairment will * * * be so diminished as no longer to pre- 
vent substantial gainful activity.”); 20 C.F.R. 404.1502(f ) 
(1961) (same); Social Security Ruling (SSR) 73-7c, at 122-123 
(Cum. ed. 1971-1975) (“The two components of disability”— 
the impairment and the inability to engage in substantial 

3 If a State does not assume responsibility for making initial eligibility 
determinations, the Commissioner must make those determinations. 42 
U.S.C. 421(b). 

7 

gainful activity by reason of the impairment—“must exist at 
the same time.”). 

Following notice-and-comment rulemaking, the Commis- 
sioner last year reaffirmed that “longstanding” construction. 
Determining Disability and Blindness; Substantial Gainful 
Activity Guides, 65 Fed. Reg. 42,772, 42,774 (2000); see also 
Notice of Proposed Rulemaking, 60 Fed. Reg. 12,166 (1995). 
The Commissioner explained that “the duration requirement 
to establish disability will not be met and a disability claim 
will be denied” if, “within 12 months after the onset of an im- 
pairment which prevented substantial gainful activity and 
before [the agency] ha[s] issued any notice of determination 
or decision finding disability, the impairment no longer pre- 
vents substantial gainful activity.” 65 Fed. Reg. at 42,774. 
The Commissioner’s regulations similarly declare that, when 
the claimant is “working and the work [he is] doing is sub- 
stantial gainful activity,” the agency “will find that [the 
claimant is] not disabled regardless of [his] medical condition 
or [his] age, education, and work experience.” 20 C.F.R. 
404.1520(b) (2000); see also 20 C.F.R. 404.1520(f ), 404.1571.4 

The determination whether a disability “has lasted or can 
be expected to last for * * * not less than 12 months” is 
made in light of the evidence available at the time the state 
agency, ALJ, or Appeals Council adjudicates the claim. See 
65 Fed. Reg. at 42,780. As a result, if the claim is adjudi- 
cated more than 12 months after the alleged disability’s on- 
set, the evidence may show that the impairment in fact al- 

4 The fact that a claimant is able to engage in substantial gainful 
activity at the time of the disability determination does not preclude the 
agency from concluding that the claimant was previously unable to engage 
in substantial gainful activity for 12 consecutive months, and that the 
claimant is therefore entitled to benefits. For example, if the claimant was 
“disabled” for the requisite period of time in the past, but has ceased to be 
disabled, the agency may award him benefits for what is called a “closed 
period” of disability. See, e.g., Social Security Program Operations Manual, 
§ 25510.001 (2001); 65 Fed. Reg. at 42,774. 

8 

ready has persisted with sufficient severity to prevent the 
claimant from being able to perform substantial gainful ac- 
tivity for the minimum 12-month period. Conversely, the 
evidence may prove that the impairment already has not 
persisted (and therefore cannot be “expected” to persist) at a 
disabling level of severity for 12 months. See id. at 42,774, 
42,780. 

Because the Act permits benefits to be awarded if the 
claimant is unable to engage in substantial gainful activity by 
reason of an impairment that “can be expected to last” 12 
months, 42 U.S.C. 423(d)(1)(A) (emphasis added), disability 
claims can be—and often are—adjudicated “without having 
to wait 12 months from onset.” 65 Fed. Reg. at 42,774.5 In 
that situation, the statute “require[s] * * * a prediction 
that the worker’s disability will continue for a total of at 
least 12 calendar months after onset of the disability” in or- 
der for benefits to be awarded. S. Rep. No. 404, supra, at 99. 
But if the alleged disability already “has existed for 12 calen- 
dar months or more” at the time the claim is adjudicated, “no 
[such] prognosis [is] required”; the Commissioner may rely 
on the claimant’s actual experience during the 12-month 
period. Ibid.; see also 65 Fed. Reg. at 42,774. 

b. Trial work. The Commissioner recently issued regula- 
tions addressing the nine-month trial work period under Ti- 
tle II. 20 C.F.R. 404.1592 (as added by 65 Fed. Reg. at 
42,787). An individual is not entitled to a trial work period 
unless he is “entitled to disability insurance benefits.” 42 
U.S.C. 422(c)(3). Accordingly, the Commissioner has con- 
cluded that entitlement to a trial work period—like the en- 
titlement to benefits—is contingent on the claimant’s having 
suffered or being expected to suffer from an impairment of 

5 The average processing time for initial disability determinations 
by the Commissioner is about three and a half months. See Performance 
Plan for Fiscal Year 2002, at 77 <http://www.ssa.gov/performance/2002/ 

2002perfplan.pdf>. 

9 

sufficient severity to prevent the performance of substantial 
gainful activity for at least 12 months. SSR 82-52, at 328 
(Cum. ed. 1981-1985). Consequently, if the Commissioner 
has not already determined that the claimant is expected to 
be unable to work for at least 12 months by reason of the 
impairment, and if the individual in fact successfully returns 
to work within 12 months of the onset of the alleged 
disability and before the Commissioner makes such a 
determination, the claimant is not entitled to disability 
insurance benefits or, therefore, to a trial work period. See 
20 C.F.R. 404.1592(d)(2) (as added by 65 Fed. Reg. at 42,787) 
(“You are not entitled to a trial work period” if “you perform 
work demonstrating the ability to engage in substantial 
gainful activity * * * before the date of any notice of 
determination or decision finding that you are disabled.”). 

B. Proceedings in this Case 

1. In March 1995, respondent Cleveland Walton applied 
for disability insurance benefits under Title II and SSI bene- 
fits under Title XVI. Respondent had been terminated from 
his job as an in-school suspension teacher on October 31, 
1994, and, following several unsuccessful attempts to return 
to work, had been diagnosed in March 1995 as having schizo- 
phrenia. In May of that year, less than seven months after 
his work as a teacher had ended and three months after ap- 
plying for disability insurance benefits, respondent began 
working part-time as a cashier at a grocery store. His work 
hours gradually increased, and by October 1995, he earned 
more than $500 a month. Respondent began to work full 
time at the grocery store in December 1995, and he worked 
there successfully for two more years before being sus- 
pended for selling alcohol to a minor. Pet. App. 53a-54a; 
Admin. Rec. 440, 444. 

In August 1996, the ALJ determined that respondent was 
disabled for the period between October 31, 1994, when he 
was discharged by the school district, and December 1995, 

10 

when he began to work full-time at the grocery store. Pet. 
App. 52a-61a. SSA’s Appeals Council remanded the case to 
the ALJ to determine whether respondent had engaged in 
substantial gainful activity before December 1995 and within 
one year of the onset of his alleged disability. Under SSR 
82-52, the Appeals Council noted, such activity, if it occurs 
before the lapse of the 12-month period following onset of 
the impairment and before the claimant has been found dis- 
abled, requires a denial of benefits. Id. at 47a-51a. 

On remand, the ALJ denied respondent’s claim for bene- 
fits. Pet. App. 39a-46a. Like the Appeals Council, the ALJ 
noted that the Commissioner’s construction of the Act, set 
forth in SSR 82-52, provides that a claim must be denied 
when a claimant successfully returns to work (and thereby 
demonstrates the ability to perform substantial gainful ac- 
tivity) within 12 months of the alleged disability’s onset. See 
Pet. App. 41a (The “duration requirement provides that [the 
claimant] must be prevented from performing substantial 
gainful activity [by reason of the impairment] for a 12-month 
period even if his impairment lasted or was expected to last 
for 12 months.”). Reviewing the evidence and applying the 
regulatory criteria for determining whether work consti- 
tutes substantial gainful activity, the ALJ concluded that 
respondent in fact had “returned to substantial gainful ac- 
tivity in October 1995,” because his earnings for that month 
were in excess of $500. Id. at 41a-44a.6 The ALJ therefore 

6 Congress directed the Commissioner to “prescribe” by regulation 
“the criteria” for determining when “services performed or earnings de- 
rived from services demonstrate an individual’s ability to engage in 
substantial gainful activity.” 42 U.S.C. 423(d)(4)(A) (1994 & Supp. V 1999). 
An applicant “whose services or earnings meet such criteria, shall * * * 
be found not to be disabled.” Ibid. Pursuant to that authority, the Com- 
missioner issued regulations providing that work was rebuttably pre- 
sumed to be substantial gainful activity if the claimant earned more than 
$500 in a month. 20 C.F.R. 404.1574(b)(2)(2000). The Commissioner, after 
this case was decided, increased that amount to $700. 20 C.F.R. 
404.1574(b)(2)(2001). 

11 

concluded that respondent could “not be found to be under a 
‘disability’ ” because his impairment had not “prevented 
[him] from working for any continuous period of 12 months.” 
Id. at 44a. 

The ALJ also determined that respondent was not enti- 
tled to a trial work period under Title II. Because respon- 
dent “is not under a ‘disability,’ ” the ALJ reasoned, “he is 
not entitled to * * * a trial work period under the Regula- 
tions.” Pet. App. 44a. The Appeals Council upheld the 
ALJ’s decision. Id. at 36a-38a. 

2. Respondent sought judicial review in the District 
Court for the Eastern District of Virginia. The magistrate 
judge recommended that summary judgment be granted in 
favor of the Commissioner, Pet. App. 30a-35a, and the dis- 
trict court accepted that recommendation, id. at 15a-26a. 
The magistrate and district court concluded that a claimant’s 
disability—his inability to engage in substantial gainful 
activity by reason of an impairment—and not just his im- 
pairment must last at least 12 months. In this case, they 
observed, respondent had engaged in substantial gainful 
activity within 12 months of the date of onset of his im- 
pairment. Accordingly, the magistrate and district court 
held that respondent’s claim failed at the first step of the 
five-step sequential evaluation process used for the ad- 
judication of disability claims, see Yuckert, 482 U.S. at 140; 
20 C.F.R. 404.1520(b), 416.920(b), because respondent had 
not been prevented from engaging in substantial gainful 
activity for the requisite 12-month period. See Pet. App. 
23a-24a, 33a-34a. 

The magistrate and district court also rejected respon- 
dent’s request for a trial work period. They concluded that, 
because respondent was not entitled to disability benefits, he 
was not entitled to a trial work period either. See Pet. App. 
17a-18a n.2. 

Finally, the magistrate and district court rejected respon- 
dent’s claim that “the ALJ erred in not finding him disabled 

12 

based on the fact that his impairment was ‘expected’ to last 
for a continuous period of not less than 12 months.” Pet. 
App. 34a; see id. at 24a. They concluded that the ALJ “did 
not have to consider prospectively the expectations of the 
duration of his impairment because the ALJ had the benefit 
of knowing the actual amounts [respondent] did earn during 
the period.” Id. at 34a; see id. at 24a. Those earnings “were 
consistently in excess of $500 per month beginning in Octo- 
ber, 1995,” and as high as $1,140 in December of that year. 
Id. at 34a; see id. at 24a-25a. 

3. The court of appeals reversed. Pet. App. 1a-14a. It 
agreed with the ALJ and the district court that respondent 
had engaged in substantial work activity in October 1995, 
less than 12 months after the alleged disability’s onset. Id. 
at 2a-3a n.1, 5a. But it rejected the Commissioner’s and the 
district court’s conclusion that respondent was ineligible for 
benefits as a result. Id. at 6a. 

a. The court of appeals first examined the Commis- 
sioner’s interpretation of the Act, which requires that the 
claimant’s impairment have lasted, or be expected to last, for 
at least 12 continuous months at a level of severity sufficient 
to preclude substantial gainful activity. Applying the two- 
step test of Chevron U.S.A. Inc. v. Natural Resources De- 
fense Council, Inc., 467 U.S. 837 (1984), the court rejected 
the Commissioner’s approach at Chevron step one because, 
in the court’s view, it was contrary to the “clear and unambi- 
guous” language of the statute. Pet. App. 6a. The court rea- 
soned that the phrase “which has lasted or can be expected 
to last for a continuous period of not less than 12 months” in 
42 U.S.C. 423(d)(1)(A) modifies “impairment,” not “inability 
to engage in SGA.” Id. at 7a-8a; see id. at 11a. It follows, the 
court believed, that “a claimant whose impairment was ‘ex- 
pected to result in death,’ or which ‘lasted’ or ‘was expected 
to last’ for a continuous period of not less than twelve 
months may be disabled, even if the inability to engage in 
substantial gainful activity does not cause death or actually 

13 

persist for twelve months.” Id. at 8a. As the court read the 
Act, no “duration requirement for the inability to engage in 
substantial gainful activity * * * exists.” Id. at 7a. 

Based on that construction of the Act, the court of appeals 
concluded that respondent was entitled to disability insur- 
ance benefits because his underlying impairments—his 
schizophrenia and depression—were expected to last and did 
last in some discernible form for more than 12 months, even 
though they did not remain so severe as to prevent him from 
engaging in substantial gainful activity for 12 months. Pet. 
App. 9a. The court pointed out that respondent did not en- 
gage in a successful work attempt until “May 1995, two 
months after the five-month waiting period” in 42 U.S.C. 
423(a) and (c)(2) had lapsed, and respondent did not engage 
in substantial gainful activity “until October 1995, well after 
the five-month waiting period had lapsed.” Pet. App. 9a. 
Under those circumstances, the court concluded, respondent 
had met the statutory requirements for entitlement to an 
award of Title II disability insurance benefits. Ibid. The 
court did not separately address respondent’s claim for SSI 
benefits under Title XVI of the Social Security Act, which 
has no waiting period. 

b. The court of appeals next held that respondent was 
entitled to a trial work period under 42 U.S.C. 422(c). Pet. 
App. 9a-10a. In the court’s view, respondent’s entitlement to 
a trial work period was “conclusively settled” by the court’s 
earlier conclusion that respondent was entitled to disability 
benefits as of April 1995, when the five-month waiting period 
under Title II expired. Id. at 9a. The court noted that the 
period of trial work begins once the claimant becomes enti- 
tled to disability benefits. Ibid. (citing 42 U.S.C. 422(c)(3), 
which provides that the “period of trial work” begins “with 
the month in which [the claimant] becomes entitled to dis- 
ability insurance benefits.”). Having found that respondent 
was entitled to benefits beginning in April 1995, the court 
found that respondent qualified for a nine-month trial work 

14 

period as of that date as well. Ibid. Because of that trial 
work period, the court held that respondent’s work in Octo- 
ber 1995, which was at a level that constituted substantial 
gainful activity, could not be used to support a determination 
that he was not disabled. Ibid. 

c. Finally, the court rejected the Commissioner’s con- 
struction of the Act as unreasonable under the second step of 
Chevron. Pet. App. 10a-13a. In so doing, the court for the 
most part repeated its textual analysis of the Act. Id. at 10a- 
11a. In addition, the court rejected as unreasonable the 
Commissioner’s position that the trial work period cannot 
begin until after either (a) benefits are granted on the expec- 
tation that the individual will not be able to work for 12 
months, or (b) the individual in fact was unable to work for 
12 consecutive months. The court acknowledged that the 
Commissioner had interpreted the phrase “can be expected 
to last” in the definition of disability as intended to enable 
the Commissioner to “ ‘adjudicate disability claims without 
having to wait 12 months from the alleged onset of disability, 
rather than to permit claims to be allowed in the face of evi- 
dence that the claimant’s impairment did not prevent sub- 
stantial gainful activity for 12 continuous months.’ ” 
Id. at 

12a (quoting 60 Fed Reg. at 12,168). The court rejected that 
interpretation because the Act does not explicitly mention 
adjudication as a prerequisite to a finding of disability; be- 
cause no other provision of the Act “differentiates between 
claims adjudicated within twelve months, and claims adjudi- 
cated after twelve months”; and because “under the Com- 
missioner’s interpretation, a finding of disability, or entitle- 
ment to benefits or a trial work period, would be determined, 
in part, by when the Commissioner adjudicated a claim.” Id. 
at 13a. 

SUMMARY OF ARGUMENT 

I. A. Congress created Title II’s disability insurance 
program in 1956 to fill a perceived gap in the social security 

15 

retirement system, which previously limited retirement 
benefits to workers who retired at age 65 or older. In par- 
ticular, Congress sought to extend benefits to “workers who 
are forced into premature retirement” before age 65 by “rea- 
son of a permanent and total disability.” H.R. Rep. No. 1189, 
84th Cong., 1st Sess. 3 (1955). Congress initially ensured 
that benefits would be limited to such workers by requiring 
that the impairment that prevents substantial gainful activ- 
ity be of long-continued and indefinite duration. Although 
Congress changed the duration requirement to “not less 
than 12 months” in 1965, it did so because experience had 
shown that, “in the great majority of cases in which total 
disability continues for at least a year the disability is essen- 
tially permanent.” S. Rep. No. 404, 89th Cong., 1st Sess., Pt. 
I, at 99 (1965). The Act thus defines “disability” as the “in- 
ability to engage in any substantial gainful activity by reason 
of any medically determinable physical or mental impair- 
ment which can be expected to result in death or which has 
lasted or can be expected to last for a continuous period of 
not less than 12 months.” 42 U.S.C. 423(d)(1)(A); 42 U.S.C. 
1382c(a)(3)(A) (1994 & Supp. V 1999). An individual, the Act 
also declares, “shall be determined to be under a disability 
only if his physical or mental impairment or impairments are 
of such severity that he” can neither “do his previous work” 
nor “engage in any other kind of substantial gainful work 
which exists in the national economy.” 42 U.S.C. 
423(d)(2)(A) (emphasis added); 42 U.S.C. 1382c(a)(3)(B) (em- 
phasis added). 

The Commissioner of Social Security has, for the more 
than four decades of the disability program’s existence, con- 
sistently interpreted Section 423(d) as requiring both that 
the claimant’s physical or mental impairment have lasted or 
be expected to last at least 12 months, and that the impair- 
ment have lasted or be expected to last that long at a level of 
severity sufficient to prevent substantial gainful activity. In 
this case, the court of appeals rejected that construction and 

16 

held that no “duration requirement for the inability to en- 
gage in substantial gainful activity * * * exists.” Pet. App. 
7a. The Act’s text, the court held, requires only that the im- 
pairment last 12 months, and therefore precludes any re- 
quirement that the disability (i.e., the inability to engage in 
substantial gainful activity on account of that impairment) 
last that long as well. Id. at 8a. The court of appeals’ deci- 
sion rests on faulty logic and a misunderstanding of the 
judicial role in construing a statute entrusted to an executive 
agency for administration. 

The court of appeals reasoned that, because 42 U.S.C. 
423(d)(1)(A) requires the impairment to have lasted or be 
expected to last 12 months, it cannot be construed as re- 
quiring the impairment to persist at a disabling level of se- 
verity during that period. But the court of appeals ignored 
the fact that Section 423(d)(1)(A) requires not merely an im- 
pairment, but also an inability to engage in substantial gain- 
ful activity “by reason of ” that impairment; the impairment 
and the resulting inability to work are thus inextricably 
linked. More fundamentally, the fact that Section 
423(d)(1)(A) requires the impairment to last for a particular 
amount of time simply does not resolve whether the impair- 
ment must persist at a specified level of severity during that 
time. Instead, it shows that Congress has not directly re- 
solved the issue of severity during the 12-month duration 
through Section 423(d)(1)(A) itself, and instead has left that 
question for the agency to resolve through the exercise of its 
expertise. Finally, the court of appeals’ analysis ignores the 
text of 42 U.S.C. 423(d)(2)(A), which requires that the im- 
pairment be so severe that it precludes all substantial gainful 
activity. The court nowhere explained why that severity 
requirement does not apply to the impairment for the entire 
12-month duration requirement. Indeed, the court of ap- 
peals’ construction is difficult to reconcile with the Act’s 
structure and evident purpose of providing disability bene- 

17 

fits to those who cannot work, not impairment compensation 
to individuals who can work. 

B. As Congress has revised the Act over the years, it has 
repeatedly concurred in the Commissioner’s construction. 
When Congress enacted the program in 1956, the House and 
Senate Reports explained that the Act provided benefits if 
the disability—statutorily defined as the “inability to engage 
in any substantial gainful activity by reason of any medically 
determinable physical or mental impairment,” 42 U.S.C. 
423(d)(1)(A)—has lasted or can be expected to last the speci- 
fied duration. After the Commissioner so construed the 
statute beginning with the 1957 regulations, Congress re- 
peatedly amended the statute in closely related respects. 
Each time it not only carefully preserved, but also specifi- 
cally reaffirmed and ratified, the Commissioner’s construc- 
tion. The Commissioner’s construction thus is not merely 
reasonable or permissible; it is the construction that Con- 
gress intended. 

C. The court of appeals’ decision cannot be reconciled 
with Congress’s deliberate decision not to provide benefits in 
cases of short-term, temporary disability. Under the court 
of appeals’ construction of the Act, no “duration requirement 
for the inability to engage in substantial gainful activity * * * 
exists.” Pet. App. 7a. It thus requires the Commissioner to 
process claims for and award Title II insurance benefits to 
individuals whose impairments prevent substantial gainful 
activity for as little as five months, and to process claims for 
and pay Title XVI SSI disability benefits to claimants who 
suffer an inability to engage in substantial gainful activity of 
virtually any duration, however brief. That result is incon- 
sistent with Congress’s intent, and its specific decision to re- 
ject a reduced disability duration period of six months that, 
in Congress’s view, would have awarded benefits in cases of 
short-term, temporary disabilities. 

II. A. 

The court of appeals also misconstrued 42 U.S.C. 

422(c), which governs trial work periods. Under Section 422, 

18 

the trial work period begins with the month in which the 
claimant “becomes entitled to disability insurance benefits.” 
42 U.S.C. 422(c)(3). In this case, respondent never became 
entitled to benefits because, by the time his claim was adju- 
dicated, respondent had returned to substantial gainful ac- 
tivity within 12 months of his disability’s onset; in other 
words, his disability did not last (and therefore could not be 
expected to last) the required 12-month period. Because re- 
spondent never became “entitled” to benefits, the trial work 
period never began to run. 

B. The Commissioner’s trial work regulations are, in any 
event, entirely consistent with and reasonably implement 
the text of the Social Security Act. They precisely reflect, 
moreover, how Congress expected disability determinations 
would be made. 

The court of appeals erred in invalidating the Commis- 
sioner’s trial work regulations based on its concern that enti- 
tlement to benefits (and thus to a trial work period) might, 
under them, occasionally depend on when the claim is adju- 
dicated. Although some claims may be affected by when 
they are determined, that is a necessary (if regrettable) con- 
sequence of permitting the agency “to adjudicate disability 
claims and award benefits without having to wait 12 months 
from onset” and the necessity, when so doing, of relying on 
potentially faulty predictions about the disability’s duration. 
65 Fed. Reg. at 42,780. Besides, decisions in other legal con- 
texts, particularly ones requiring predictive judgments, are 
likewise influenced by when the adjudication takes place. 
Juries, for example, may consider an individual’s post-claim, 
pre-trial behavior—such as successful rehabilitation—when 
assessing the extent or duration of a claimed injury, even 
though that evidence might have been unavailable if trial 
had occurred earlier. Yet no one suggests that courts must 
fashion an exclusionary rule for such evidence to avoid that 
result. Similarly, nothing compels the Commissioner to ig- 
nore evidence showing the precise duration of a claimant’s 

19 

disabling impairment simply because it would have been un- 
available if the claim had been adjudicated earlier. 

ARGUMENT 

I. THE SOCIAL SECURITY ACT DOES NOT PROVIDE 

DISABILITY BENEFITS TO A CLAIMANT WHOSE 
IMPAIRMENT HAS NOT LASTED AND CANNOT BE 

EXPECTED TO LAST 12 MONTHS AT A DIS- 
ABLING LEVEL OF SEVERITY 

As enacted in 1935, the Social Security Act provided re- 
tirement benefits to covered workers who retired at age 65, 
but did not provide benefits to workers who were “demon- 
strably retired” before that age “by reason of a permanent 
and total disability.” See H.R. Rep. No. 1189, 84th Cong., 1st 
Sess. 3 (1955). To close that “gap” in the Act’s coverage, 
ibid., Congress in 1956 established a program of disability 
insurance under Title II of the Act. Social Security Amend- 
ments of 1956, ch. 836, § 103, 70 Stat. 815. The Act now de- 
fines “disability” as the “inability to engage in any substan- 
tial gainful activity by reason of any medically determinable 
physical or mental impairment which can be expected to re- 
sult in death or which has lasted or can be expected to last 
for a continuous period of not less than 12 months.” 42 
U.S.C. 423(d)(1)(A). The Act further provides that an indi- 
vidual “shall be determined to be under a disability only if 
his physical or mental impairment or impairments are of 
such severity” that he can neither “do his previous work” 
nor “engage in any other kind of substantial gainful work 
which exists in the national economy.” 42 U.S.C. 
423(d)(2)(A) (emphasis added). Congress used those same 
definitions in 1972 when it established the Title XVI Sup- 
plemental Security Income program, which provides pay- 
ments to disabled individuals who are financially needy. See 
42 U.S.C. 1382c(a)(3)(A) (1994 & Supp. V 1999); 42 U.S.C. 
1382c(a)(3)(B). 

20 

The Commissioner of Social Security has always inter- 
preted and administered the Act to require both that the 
claimant’s physical or mental impairment have lasted or be 
expected to last at least 12 months, and that the impairment 
have lasted or be expected to last that long at a level of se- 
verity sufficient to prevent substantial gainful activity. See 
pp. 24-27, infra. As the Commissioner recently explained 
following a notice-and-comment rulemaking, the “duration 
requirement to establish disability will not be met and a dis- 
ability claim will be denied” if, “within 12 months after the 
onset of an impairment which prevented substantial gainful 
activity and before [the agency] ha[s] issued any notice of 
determination or decision finding disability, the impairment 
no longer prevents substantial gainful activity.” Determin- 
ing Disability and Blindness; Substantial Gainful Activity 
Guides, 65 Fed. Reg. 42,772, 42,774 (2000). 

In revisiting and revising the disability provisions of the 
Social Security Act over the years, Congress too has consis- 
tently acted on the understanding that the disability—the 
“inability to engage in any substantial gainful activity by 
reason of any medically determinable physical or mental im- 
pairment,” 42 U.S.C. 423(d)(1)(A)—must have lasted or be 
expected to last at least 12-months. See, e.g., S. Rep. No. 
404, 89th Cong., 1st Sess., Pt. I, at 98-99 (1965) (Act “pro- 
vide[s] for the payment of disability benefits for an insured 
worker who has been or can be expected to be totally dis- 
abled throughout a continuous period of 12 calendar 
months” (emphasis added)); H.R. Rep. No. 231, 92d Cong., 
1st Sess. 56 (1971) (“No benefit is payable * * * unless the 
disability is expected to last (or has lasted) at least 12 con- 
secutive months.” (emphasis added)). Indeed, when Con- 
gress amended the definition of disability in 1965 to replace 
the “long-continued and indefinite duration” requirement 
with a 12-month duration requirement, it chose 12 months 
because, “in the great majority of cases in which total dis- 
ability continues for at least a year the disability is essen- 

21 

tially permanent.” S. Rep. No. 404, supra, at 99 (emphasis 
added). And when Congress amended the definition of dis- 
ability again in 1967 by adding the limitations in Section 
423(d)(2)(A), which expressly condition a finding of disability 
on the claimant’s inability to perform substantial gainful ac- 
tivity, it “reaffirm[ed] that” a claimant “who does substantial 
gainful work despite an impairment or impairments * * * 
is not disabled for purposes of establishing a period of dis- 
ability or for social security benefits based on disability dur- 
ing any period in which such work is performed.” S. Rep. 
No. 744, 90th Cong., 1st Sess. 49 (1967). 

The court of appeals in this case nevertheless held that no 
“duration requirement for the inability to engage in substan- 
tial gainful activity * * * exists.” Pet. App. 7a. Rejecting 
repeated expressions of congressional intent and the Com- 
missioner’s longstanding construction of the Act, the court of 
appeals read the text of 42 U.S.C. 423(d)(1)(A) to require 
only that the claimant’s impairment last at least 12 months, 
and, in addition, to preclude the Commissioner from con- 
struing the Act to require that the claimant’s disability—i.e., 
his “inability to engage in any substantial gainful activity by 
reason of ” that impairment—last at least 12 months as well. 
Id. at 8a. The court of appeals’ construction of the statute, 
however, ignores the express statutory link (“by reason of ”) 
between the underlying impairment and the resulting 
inability to engage in substantial gainful activity. It also 
rests on faulty logic—that because the Act requires the 
impairment to last 12 months, it cannot also be construed to 
require the impairment to persist at a disabling level of se- 
verity for that 12-month period. The court’s analysis, more- 
over, erroneously ignores the additional limitation on the 
definition of disability in Section 423(d)(2)(A), contravenes 
Congress’s repeatedly expressed intent, and is at war with 
the Act’s purpose of establishing a program for individuals 
who have long-term disabilities. Indeed, Congress has 
consistently rejected proposals that would extend Titles II 

22 

and XVI’s coverage from long-term disabilities to short-term 
disabilities. Yet, the court of appeals’ construction effects 
precisely such an extension, requiring the award of SSI 
benefits, for example, if an impairment causes an inability to 
work of virtually any duration. 

A. The Commissioner Has Reasonably Construed The Act 

To Require That A Claimant’s Inability To Engage In 
Substantial Gainful Activity Last For 12 Months 

Where an Act of Congress speaks clearly “to the precise 
question at issue,” the court “must give effect to the unam- 
biguously expressed intent of Congress.” Chevron U.S.A. 
Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 842, 843 
(1984). If “the statute is silent or ambiguous with respect to 
the specific issue,” however, the court must sustain an 
agency’s interpretation if it is “based on a permissible con- 
struction of the statute.” Id. at 843; see also Regions Hosp. 

v. Shalala, 522 U.S. 448, 457 (1998) (“If the agency’s reading 
fills a gap or defines a term in a reasonable way in light of 
the Legislature’s design, we give that reading controlling 
weight”). That deference is particularly appropriate where, 
as here, Congress has accorded the Commissioner power to 
issue legislative rules, 42 U.S.C. 405(a) (rulemaking author- 
ity); see Sullivan v. Zebley, 493 U.S. 521, 528 (1990); Yuck- 
ert, 482 U.S. at 145; Heckler v. Campbell, 461 U.S. 458, 466 
(1983), made applicable to Title XVI by 42 U.S.C. 1383(d)(1); 
and to issue written guidelines for state agencies to follow in 
adjudicating claims, 42 U.S.C. 421(a)(2) (requiring States to 
make disability determinations “in accordance with * * * 
the standards and criteria contained in regulations or other 
written guidelines of the Commissioner of Social Security”), 
made applicable to Title XVI by 42 U.S.C. 1383b(a). In such 
circumstances, the standards adopted by the Commissioner 
have “legislative effect” and are entitled “to more than mere 
deference or weight.” Batterton v. Francis, 432 U.S. 416, 
425, 426 (1977) (addressing statute requiring States to com- 

23 

ply “with standards prescribed by the Secretary”). Rather, 
the Commissioner’s construction must be “given controlling 
weight” unless it is “arbitrary, capricious, or manifestly con- 
trary to the statute.” Zebley, 493 U.S. at 528 (quoting Chev- 
ron, 467 U.S. at 843-844). Moreover, as this Court has recog- 
nized, the “Social Security Act is among the most intricate 
ever drafted by Congress. * * * Perhaps appreciating the 
complexity of what it had wrought, Congress conferred on 
the [Commissioner] exceptionally broad authority to pre- 
scribe standards for applying certain sections of the Act.” 
Schweiker v. Gray Panthers, 453 U.S. 34, 43 (1981). Under 
these principles, the Commissioner’s interpretation of the 
Act should be sustained. 

1. The text of the Social Security Act does not directly 
resolve the precise question before the Court. The Act de- 
fines disability in part as the “inability to engage in any sub- 
stantial gainful activity by reason of any medically deter- 
minable physical or mental impairment which can be ex- 
pected to result in death or which has lasted or can be ex- 
pected to last for a continuous period of not less than 12 
months.” 42 U.S.C. 423(d)(1)(A). By its terms, Section 
423(d)(1)(A) requires that the impairment have lasted or be 
expected to last 12 months (or result in death). But Section 
423(d)(1)(A) does not speak directly to whether the impair- 
ment must persist during those 12 months at any particular 
level of severity—in particular, whether it must be suffi- 
ciently severe to prevent substantial gainful activity. Nor 
does it specify how long the disability—the inability to work 
“by reason of ” the impairment—must last. On those issues, 
Section 423(d)(1)(A) is ambiguous. 

In 1967, Congress added Section 423(d)(2)(A) to supple- 
ment and clarify the basic definition of “disability.” Section 
423(d)(2)(A) provides that, “[f]or purposes of paragraph 
[d](1)(A)”—the basic definition of disability—a claimant 
“shall be determined to be under a disability only if his 
physical or mental impairment or impairments are of such 

24 

severity that he is not only unable to do his previous work 
but cannot, considering his age, education, and work experi- 
ence, engage in any other kind of substantial gainful work 
which exists in the national economy.” 42 U.S.C. 423(d)(2) 
(A) (emphasis added). By amending the Act to add Section 
423(d)(2)(A), Congress made it clear that, for purposes of 
disabilit determinations, it is not sufficient that there merely 
be some sort of discernible impairment. Instead, there must 
be an impairment that is sufficiently severe to preclude any 
substantial gainful activity. 

2. The Commissioner has consistently construed Section 
423(d) to mean that a claimant is not entitled to disability 
benefits unless, during the 12 months for which the impair- 
ment has persisted or can be expected to persist, the im- 
pairment is so severe that it precludes substantial gainful 
activity. After the 1956 amendments, in which Congress 
first afforded benefits for insured workers who were dis- 
abled by impairments of “long-continued and indefinite dura- 
tion,” the Commissioner immediately interpreted the Act as 
requiring the impairment to persist at a disabling level of 
severity for the specified duration (“long-continued and in- 
definite”). The Commissioner’s regulations, issued in 1957, 
see 22 Fed. Reg. 4362, 4363, provided that an impairment is 
of long-continued and indefinite duration under the Act only 
if “it cannot reasonably be anticipated that the impairment 
will, in the foreseeable future, be so diminished as no longer 
to prevent substantial gainful activity.” 20 C.F.R. 404.1502(f ) 
(1960 Supp.) (emphasis added); 20 C.F.R. 404.1502(f ) (1961) 
(same); see also 20 C.F.R. 404.1520(g) (1961) (“An individual 
will be deemed not under a disability if, with reasonable 
effort and safety to himself, the impairment can be dimin- 
ished to the extent that the individual will not be prevented 
by the impairment from engaging in any substantial gainful 
activity.”). The Commissioner’s written instructions to the 
States, which must make disability determinations “in 
accordance with * * * the standards and criteria contained 

25 

in” the Commissioner’s “written guidelines,” 42 U.S.C. 
421(a)(1) and (2), also made that clear. See OASI Disability 
Insurance Letter No. 39 (Pt. V of Disability Insurance State 
Manual), at 1 (Jan. 22, 1957) (“long-continued and indefinite 
duration” requirement refers to the “expected duration of 
the medical impairment” at a “level of severity sufficient to 
preclude SGA”). 

After Congress changed the duration requirement from 
“long-continued and indefinite” to “not less than 12 months” 
in 1965, the Commissioner continued to require that the im- 
pairment persist at a disabling level of severity for the speci- 
fied period. The impairment, the Commissioner explained, 
must be “expected to last at a disabling level for 12 months 
or more from onset.” SSA Disability Insurance Letter No. 
III-6 (Pt. III of Disability Insurance State Manual), at 4 
(Nov. 19, 1965) (emphasis added); Disability Insurance State 
Manual, § 316 (Sept. 9, 1965) (“Duration of impairment refers 
to that period of time during which an individual is continu- 
ously unable to engage in substantial gainful activity be- 
cause of a medically determinable physical or mental im- 
pairment.”) (emphasis added).7 

7 See also Disability State Insurance Manual, § 316.1-A (Sept. 9, 1965) 
(“Where the claimant is engaging in SGA, or is held to be able to engage in 
SGA * * *, a finding of disability may be made if the impairment pre- 
vented the claimant from engaging in SGA for at least 12 consecutive 
months.”); id. at § 316.1-C (where adjudication occurs “before the im- 
pairment has lasted 12 months,” the decisionmaker must examine the 
evidence to determine “whether the impairment will continue to prevent 
the individual from engaging in SGA for the additional number of months 
needed to make up the required 12 months duration”); SSA, Concepts of 
Disability and Principles of Evaluation, at 3 (Jan. 1966) (Because “the 
disabling impairment must have lasted or be expected to last 12 con- 
tinuous months from onset,” an “impairment which became incapacitating 
on April 12 must have continued or be expected to continue at a disabling 
level into April 11 of the following year.”); SSA Disability Insurance 
Letter No. II-24 (Pt. II of Disability Insurance State Manual), at 4 (Aug. 
30, 1965) (“In all cases, use existing guides for determining whether the 
claimant is able to engage in any SGA since the 1965 Amendments made 

26 

The Commissioner has never wavered from that construc- 
tion. See, e.g., Social Security Ruling (SSR) 73-7c, at 122-123 
(Cum. ed. 1971-1975) (adopting construction, set forth in 
Alexander v. Richardson, 451 F.2d 1185, 1186 (10th Cir. 
1971), cert. denied, 407 U.S. 911 (1972), under which both 
“components of disability”—the impairment and the result- 
ing inability to work—“must exist at the same time to satisfy 
the twelve month duration requirement”); SSR 82-52, at 328 
(Cum. ed. 1981-1985) (“In considering ‘duration,’ it is the in- 
ability to engage in SGA because of the impairment that 
must last the required 12-month period.”); 20 C.F.R. 
404.1520(b) (2000) (when the claimant is “working and the 
work [he is] doing is substantial gainful activity,” the agency 
“will find that [the claimant is] not disabled regardless of 
[his] medical condition or [his] age, education, and work 
experience.”); 20 C.F.R. 404.1520(f ) (2000) (“Your impair- 
ment(s) must prevent you from doing any other work.”); 20 
C.F.R. 404.1571 (2000) (“If you are able to engage in sub- 
stantial gainful activity, we will find that you are not dis- 
abled.”). Thus, as the Commissioner explained in promul- 
gating the most recent regulations, it has been the agency’s 
“longstanding” position that “the duration requirement to 
establish disability will not be met” if the “impairment no 

no change with respect to the issue of severity. * * * [U]nder the 1965 
Amendments the impairment, which prevents SGA, must have lasted or 
be expected to last 12 months from onset of disability. * * * An in- 
dividual with a disabling impairment * * * would be found under a 
disability if he is undergoing therapy * * * and his disability, none- 
theless, has lasted or is expected to last 12 months from onset. If it is 
found that the claimant is able to engage in SGA in accordance with 
existing criteria, a finding of ‘no disability’ should be made. If it is found 
that, although the claimant is currently unable to engage in SGA, in 
accordance with existing criteria, he is expected to be able to engage in 
SGA within 12 months from onset, a finding of ‘no disability’ should be 
made.”); SSA Disability Insurance Letter No. III-6, supra, at 1, 4, 6 (1965 
amendments “made no change in the severity requirement”; thus im- 
pairments must be “expected to last at a disabling level for 12 months or 
more from onset.”). 

27 

longer prevents substantial gainful activity” before the 12- 
month period has lapsed. 65 Fed. Reg. at 42,774.8 

3. The Commissioner’s construction is fully supported by 
the Act’s text and structure. Section 423(d)(1)(A) requires 
not only that there be an underlying “impairment” lasting 
the specified duration, but also an inability to engage in sub- 
stantial gainful activity “by reason of ” that impairment. 42 
U.S.C. 423(d)(1)(A). The impairment and the resulting in- 
ability to work thus are inextricably linked. Furthermore, 
Section 423(d)(2)(A) expressly provides that a claimant may 
be found disabled “only if ” his impairment is of “such sever- 
ity” as to render him unable to perform any substantial gain- 
ful work that exists in the national economy. It therefore is 
entirely reasonable for the Commissioner to construe the 
Act to require that the impairment that must last at least 12 
months under Section 423(d)(1)(A) be one that is of “such 
severity” as to satisfy Section 423(d)(2)(A) during those 12 
months. 

Indeed, prior to the Fourth Circuit’s decision in this case, 
the courts of appeals had repeatedly upheld the Commis- 
sioner’s interpretation of Section 423(d) to require that both 
the underlying impairment and the resulting inability to en- 
gage in substantial gainful activity must have lasted or be 
expected to last for the statutory 12-month period. For ex- 
ample, in Alexander, 451 F.2d at 1186, the Tenth Circuit re- 
jected the reasoning that was adopted by the Fourth Circuit 
in this case, and affirmed the Commissioner’s decision deny- 
ing benefits because the “disability extended for a period of 
less than twelve months, although there was an impairment 

8 A claimant’s unsuccessful attempt to return to work before the ex- 
piration of the 12-month disability period will not prevent the claimant 
from being entitled to disability benefits. The Commissioner “will disre- 
gard work attempts lasting 6 months or less that do not demonstrate the 
ability to perform sustained substantial gainful activity even if the un- 
successful work attempt occurs prior to adjudication of the claim for bene- 
fits.” 65 Fed. Reg. at 42,780. See 20 C.F.R. 404.1574(c), 404.1575(d) (2001). 

28 

which lasted for more than one year.” Id. at 1186. The court 
explained: 

To recover disability benefits under the Act an applicant 
must be unable to engage in any substantial gainful ac- 
tivity. Disability is established by showing a medically 
determinable mental or physical impairment which pre- 
vents [the claimant from] engaging in any gainful activ- 
ity. Inability to engage in any gainful activity and the 
impairment which causes it cannot be separated. The 
two components of disability must exist at the same time 
to satisfy the twelve month duration requirement. 

Ibid. Other courts of appeals have agreed. See Titus v. Sul- 
livan, 4 F.3d 590, 594 (8th Cir. 1993) (“We agree with the 
district court that the interpretation of ‘duration of impair- 
ment’ was settled in Alexander v. Richardson, 451 F.2d 1185 
(10th Cir. 1971).”). See also McDonald v. Bowen, 818 F.2d 
559, 564 (7th Cir. 1986) (the “disability” must be “expected to 
last at least twelve continuous months from its alleged onset 
date; otherwise she will not receive benefits”); Estep v. 
Richardson, 459 F.2d 1015, 1016 (4th Cir. 1972) (“To obtain 
disability benefits under the Act a claimant must have an 
impairment which prevents him from engaging in substantial 
gainful activity for a period of at least 12 months.”). 

4. The Commissioner’s construction of the Act is not only 
consistent with the Act’s text but is also firmly grounded in 
common sense. Workers often may have impairments that 
last longer than a year, but that prevent them from being 
able to work only for a much shorter time. See, e.g., Alexan- 
der, 451 F.2d at 1186 (“For example, an applicant may have 
an injury from which he has lost one of his hands. The result 
is a physical impairment for the remainder of his life, but if 
he is able to engage in any gainful activities within a year 
from his injury he is not entitled to benefits.”). In fact, many 
relatively common ailments—from bac 
injuries, to high blood 

pressure, to carpal tunnel syndrome—may predictably last a 

29 

lifetime, but may preclude the individual from working only 
briefly or for relatively brief, intermittent periods. Titles II 
and XVI of the Act, however, were designed to provide dis- 
ability benefits to persons who cannot engage in substantial 
gainful activity, not to provide impairment benefits to those 
who can. 

Congress originally enacted the disability insurance pro- 
gram to fill a “gap” in Social Security’s retirement system by 
providing benefits to those “forced into premature retire- 
ment” before age 65 “by reason of a permanent and total 
disability.” H.R. Rep. No. 1189, supra, at 3 (emphasis added). 
See pp. 2, 19, supra; see also pp. 39-40, infra (discussing Con- 
gress’s rejection of benefits for short-term disabilities). It is 
thus the sustained inability to work on account of an im- 
pairment, not the impairment alone without regard to its 
effect on the claimant, that gives rise to the need and justifi- 
cation for the payment of disability benefits. 

5. The court of appeals nevertheless rejected the Com- 
missioner’s construction, holding that the definition of “dis- 
ability” in Section 423(d)(1)(A) precludes the Commissioner 
from construing the Act to require that the inability to en- 
gage in substantial gainful activity have lasted, or be ex- 
pected to last, at least 12 months. The court of appeals, how- 
ever, did not identify any provision of the Act that expressly 
states that there is no “duration requirement for the inabil- 
ity to engage in substantial gainful activity.” Pet. App. 7a. 
It did not identify any provision stating that the impairment 
need not persist at a disabling level of severity for the statu- 
tory 12-month period. And it offered no plausible reason 
why Congress would have insisted that the underlying im- 
pairment last for 12 months but not the claimant’s inability 
to work “by reason of ” that impairment. Instead, the court 
relied on the observation that, as a matter of grammar, the 
phrase “which has lasted or can be expected to last for not 
less than 12 months” in Section 423(d)(1)(A) modifies the 
word “impairment,” and not the phrase “inability to engage 

30 

in any substantial gainful activity.” Id. at 7a-8a. Accord- 
ingly, the court declared, there is no duration requirement 
for the disability, id. at 7a, and a claimant is disabled if he 
has an impairment that has lasted or is expected to last 12 
months, “even if the inability to engage in substantial gainful 
activity” on account of the impairment “does not * * * 
actually persist for twelve months.” Id. at 8a. 

As a matter of grammar, the court of appeals is correct 
that the phrase “which has lasted or can be expected to last” 
in Section 423(d)(1)(A) modifies the word “impairment.” 
Section 423(d)(1)(A) therefore does expressly require that 
the impairment last at least 12 months. But the court of 
appeals erred in leaping from that unremarkable observation 
to the remarkable conclusion that Section 423(d)(1)(A) affir- 
matively precludes a construction under which the disability 
—the inability to engage in substantial gainful activity “by 
reason of ” the impairment—must also have lasted or be 
expected to last 12 months. In fact, the court of appeals’ 
grammatical parsing of Section 423(d)(1)(A) shows no more 
than that, while that provision clearly addresses how long 
the impairment must last, it is ambiguous regarding how 
severe the impairment must be during that 12-month period. 
In other words, it does not specifically address whether the 
impairment must persist with such severity as to preclude 
all substantial gainful activity during the qualifying period— 
much less foreclose the Commissioner from construing the 
Act to embody such a requirement. Cf. Mourning v. Family 
Publ’n Serv., Inc., 411 U.S. 356, 372-373 (1973). Because the 
text of Section 423(d)(1)(A) does not unambiguously resolve 
this issue, it is for the Commissioner, not the court of ap- 
peals, to choose among reasonable constructions. See Pau- 
ley v. Bethenergy Mines, Inc., 501 U.S. 680, 703-704 (1991).9 

9 The court of appeals’ imposition of its own construction appears 
implicitly to rest on an application of the maxim expressio unius est 
exclusio alterius. In particular, the court assumed that Congress, by 

31 

More fundamentally, the court of appeals’ analysis wholly 
ignores Section 423(d)(2)(A), which gives additional content 
to the definition of “disability.” Section 423(d)(2)(A) specifi- 
cally declares that an individual is disabled “only if ” the im- 
pairment precludes him from engaging in substantial gainful 
activity. See pp. 23-24, supra. The Commissioner has con- 
sistently concluded that the severity requirement codified in 
Section 423(d)(2)(A) applies throughout the 12-month period 

expressly requiring that the impairment last 12 months, implicitly pre- 
cluded any construction of the Act that requires any resulting disability to 
last that long as well. The maxim, however, has no application here. 
First, Congress’s provision of an express duration period for an impair- 
ment simply does not speak to, much less impliedly preclude, the Com- 
missioner from addressing how severe the impairment must be during that 
duration. Indeed, the statute itself seems to anticipate that the impair- 
ment and the inability to engage in substantial gainful activity “by reason 
of ” the impairment will be coterminous. See pp. 23-24, 27-28, supra. 

Second, as other courts of appeals have recognized, application of the 
expressio unius canon is not appropriate in cases (such as this one) that 
involve an administrative agency’s construction of a statute. Texas Rural 
Legal Aid, Inc. v. Legal Servs. Corp., 940 F.2d 685, 694 (D.C. Cir. 1991) 
(“Whatever its usefulness in other circumstances * * * th[e] canon has 
little force in the administrative setting.”); Whetsel v. Network Property 
Servs., LLC, 246 F.3d 897, 902 (7th Cir. 2001) (“[T]he canon of expressio 
unius est exclusio alterius has reduced force in the context of interpreting 
agency administered regulations and will not necessarily prevent the 
regulation from being considered ambiguous”). The reason is that an 
agency’s interpretation must be given deference unless Congress has “di- 
rectly spoken to the precise question at issue,” Chevron, 467 U.S. at 842, 
and “the expressio unius maxim, unsupported by arguments based on the 
statute’s structure or legislative history, ‘is simply too thin a reed to 
support the conclusion that Congress has clearly resolved [an] issue.’ ” 
Martini v. Federal Nat’l Mortgage Ass’n, 178 F.3d 1336, 1343 (D.C. Cir. 
1999) (quoting Texas Rural Legal Aid, 940 F.2d at 694), cert. dismissed, 
528 U.S. 1147 (2000); see also Cheney R.R. v. ICC, 902 F.2d 66, 69 (D.C. 
Cir.), cert. denied, 498 U.S. 985 (1990); Mobile Communications Corp. v. 
FCC, 77 F.3d 1399, 1404-1405 (D.C. Cir.), cert. denied, 519 U.S. 823 (1996); 
Amax Land Co. v. Quarterman, 181 F.3d 1356, 1365 (D.C. Cir. 1999). This 
case proves that point. Here, the legislative history shows that Congress 
not only lacked an intent to preclude the Commissioner’s interpretation 
and implementation, but actually contemplated them as based on the 
proper understanding of the Act. See pp. 20-21, supra; pp. 32-39, infra. 

32 

during which the impairment must persist. That construc- 
tion is directly supported by the text of Section 423(d)(1)(A), 
which requires not merely an impairment that has lasted or 
can be expected to last at least 12 months, but also an in- 
ability to engage in substantial gainful activity “by reason 
of ” that 12-month long impairment. Congress, moreover, 
has endorsed the Commissioner’s construction. When it 
amended the Act to add Section 423(d)(2)(A), it “reaf- 
firm[ed]” that an individual “who does substantial gainful 
work despite an impairment” is “not disabled for purposes of 
establishing a period of disability or for social security bene- 
fits based on disability during any period in which such work 
is performed.” S. Rep. No. 744, supra, at 49 (emphasis 
added). The court of appeals, by contrast, pointed to nothing 
in the Act that specifically precludes the Commissioner’s 
construction. 

10 

B. The Commissioner’s Interpretation Is Supported By 
the History Of Congress’s Amendments To The Act 

Even if the text of the Act does not compel the conclusion 
that Congress intended to impose a duration requirement for 
the disability—i.e., to require that the impairment be of dis- 
abling severity in each of the 12 months during which it has 
persisted or can be expected to persist—the history of the 

10 The court of appeals’ decision also places a gloss on the Act that 
seems unlikely in view of its structure. Section 423(d)(1)(A) by its terms 
speaks of an inability to engage in substantial gainful activity by reason of 
an “impairment” that either “can be expected to result in death” or “has 
lasted or can be expected to last” for at least 12 months. The first alter- 
native obviously implies an element of great severity; it is therefore 
sensible to read the second alternative, the requirement that the impair- 
ment have lasted or be expected to last for 12 months, as encompassing an 
element of substantial severity as well. By contrast, it is implausible to 
suppose that Congress commanded an award of benefits whenever a 
disabling impairment is so severe that it is expected to cause death, and 
whenever the impairment is only briefly disabling but persists for 12 
months in a relatively inconsequential form. Yet that is precisely the con- 
struction adopted by the decision below. 

33 

Act and its implementation does. It is well established that 
the proper construction of an Act of Congress may be in- 
formed by pre-existing administrative constructions of 
which Congress was aware. Cf. Lorillard v. Pons, 434 U.S. 
575, 580-581 (1978). Here, over a period that spans more 
than four decades, Congress repeatedly acknowledged the 
Commissioner’s construction, repeatedly endorsed it when 
amending the Act, and repeatedly adopted that construction 
itself. 

1. When Congress first established the disability insur- 
ance program in 1956, it provided disability benefits to cov- 
ered workers who were unable to engage in substantial gain- 
ful activity on account of an impairment of a “long-continued 
and indefinite duration.” See Social Security Amendments 
of 1956, ch. 836, § 103, 70 Stat. 815; 42 U.S.C. 423(c)(2) (1958). 
Anticipating the Commissioner’s construction, Congress un- 
derstood that provision as requiring “that the disability,” 
which was statutorily defined as the inability to work on ac- 
count of the impairment, “be of long-continued and indefinite 
duration.” H.R. Rep. No. 1189, supra, at 5. Thus, the House 
Report explained, “an individual who is able to engage in any 
substantial gainful activity will not be entitled to disability- 
insurance benefits.” Ibid. Consistent with the House Re- 
port, the Commissioner’s regulations under Section 405(a) 
and “written guidance” issued to the state agencies pursuant 
to 42 U.S.C. 421(a)(1) and (2) made it clear that the “long- 
continued and indefinite duration” requirement refers to the 
expected duration of the medical impairment at a level of 
severity sufficient to preclude substantial gainful activity. 
See pp. 24-25, supra (citing the Commissioner’s 1957 and 
1961 regulations, as well as the 1957 OASI Disability In- 
surance Letter No. 39). 

That construction is consistent not merely with the text 
and legislative history of the 1956 amendments themselves, 
but also with the “disability freeze” provisions of the Social 
Security Amendments of 1954, ch. 1206, § 106, 68 Stat. 1079, 

34 

1080, from which the language of the 1956 amendments was 
drawn. The disability freeze provisions sought to ensure 
that individuals who had worked a sufficient amount of time 
to qualify for retirement benefits did not find their entitle- 
ments substantially reduced because of a sustained period of 
disability—i.e., inability to engage in substantial gainful ac- 
tivity by reason of an impairment—prior to retirement. 
That could occur before 1954 because benefits were calcu- 
lated as a percentage of the worker’s average earnings. The 
1954 disability freeze provisions excluded from consideration 
the periods during which the worker was unable to engage in 
substantial gainful activity because of a disability. The 
committee reports on the 1954 amendments reveal an expec- 
tation that the inability to work had to be long-lasting before 
the disability freeze provisions could be invoked. See H.R. 
Rep. No. 1698, 83d Cong., 2d Sess. 2-3 (1954) (“Long periods 
of absence from covered work generally indicate that the 
individual has not been dependent on his own earnings from 
work for support, and benefits are properly reduced or not 
paid in such circumstances,” except in “the case of workers 
who are out of employment by reason of a total disability 
lasting for an extended period of time.”); S. Rep. No. 1987, 
83d Cong., 2d Sess. 20 (1954) (disability freeze redresses pro- 
blem that, under present law, a worker’s “old-age and sur- 
vivors insurance rights are impaired or may be lost entirely 
when workers have periods of total disability before reach- 
ing retirement age.”). 

11 

11 The 1954 committee reports also state that the “long-continued and 
indefinite duration” requirement “refers only to the duration of the 
impairment and does not require a prediction of a continued inability to 
work.” H.R. Rep. No. 1698, supra, at 23; S. Rep. No. 1987, supra, at 21. 
Those statements, however, are inconsistent with Congress’s expectation 
that the period of disability would be lengthy, and were subsequently 
refuted by the reports accompanying the enactment of Section 
423(d)(1)(A) in 1956 and subsequent amendments, see p. 33, supra; pp. 35- 
39, infra, which express the expectation that the disability must last as 
long as the impairment. Moreover, in 1954, when the disability freeze 

35 

2. When Congress amended Section 423(d) in the Social 
Security Amendments of 1965, Pub. L. No. 89-97, § 303(a)(1), 
79 Stat. 366, it was well aware of the Commissioner’s con- 
struction. The House Report on the bill noted that, “[u]nder 
present law,” benefits are “payable only if the worker’s 
disability”—i.e., the inability to engage in substantial gainful 
activity by reason of the impairment—“is expected * * * to 
be of long-continued and indefinite duration.” H.R. Rep. No. 
213, 89th Cong., 1st Sess. 88 (1965) (emphasis added). 
Although Congress changed the duration requirement from 
“long-continued and indefinite” to “not less than 12 months,” 
Congress declined to disturb the requirement that the 
impairment persist at a disabling level of severity for the 
specified period. Thus, the Senate Report explained that the 
1965 amendments “eliminate the present requirement that a 
worker’s disability must be expected to be of long-continued 
and indefinite duration, and instead provide that an insured 
worker would be eligible for disability benefits if he has been 
under a disability which * * * has lasted or can be ex- 
pected to last for a continuous period of not less than 12 cal- 

provisions were enacted, any distinction between the inability to engage in 
substantial gainful activity and the impairment giving rise to it might have 
been expected to be largely without significance insofar as duration was 
concerned. Before the 1954 amendments, benefits would be reduced or 
placed at risk when the worker’s earnings declined. If the impairment did 
not preclude substantial gainful activity and the worker’s earnings did not 
decline as a result, there would have been no need to invoke the disability 
freeze provisions. Moreover, under Section 102(b)(2) of the 1954 Amend- 
ments, the Secretary could exclude up to four years of a claimant’s work 
history from the calculation of the claimant’s “average monthly wage” if 
doing so “would produce the highest primary insurance amount.” 68 Stat. 
1063. That provision, Secretary of Health, Education, and Welfare Oveta 
Culp Hobby explained, protected workers who had “short periods of 
absence from covered work.” The Social Security Amendments of 1954: 
Hearings Before the House Comm. on Ways and Means, 83d Cong., 2d 
Sess. 68 (1954). The disability freeze provisions were thus necessary only 
to protect the rights of workers who were forced to spend “long periods 
out of the labor force” due to “a totally disabling condition.” Ibid. 

36 

endar months.” S. Rep. No. 404, supra, at 13 (emphasis 
added). The Senate Report further explained that the Act, 
as amended, “would provide for the payment of disability 
benefits for an insured worker who has been or can be ex- 
pected to be totally disabled throughout a continuous period 
of 12 calendar months.” Id. at 98 (emphasis added); see also 
id. at 13 (an insured worker is “eligible for disability benefits 
if he has been under a disability which can be expected to 
last for a continuous period of not less than 12 calendar 
months” (emphasis added)). 

12 

“It is well established that when Congress revisits a stat- 
ute giving rise to a longstanding administrative interpreta- 
tion without pertinent change, the ‘congressional failure to 
revise or repeal the agency’s interpretation is persuasive 
evidence that the interpretation is the one intended by Con- 
gress.’ ” Commodity Futures Trading Comm’n v. Schor, 478 
U.S. 833, 846 (1986); NLRB v. Bell Aerospace Co., 416 U.S. 
267, 274-275 (1974). That principle is of particular force 
where, as here, the legislative history expressly acknowl- 
edges the agency’s construction and manifests an intent to 
preserve it. 

13 

12 See also S. Rep. No. 408, 96th Cong., 1st Sess. 13 (1979) (explaining 
that, in 1965, “the definition requiring that a disability be of ‘long-con- 
tinued and indefinite duration’ was changed to permit benefits for dis- 
abilities expected to last at least 12 months.” (emphasis added)). 

13 Congress was specifically advised of the Commissioner’s construc- 
tion and the effect it would have on the proposed legislation. Testifying 
before a congressional committee on the then-pending proposal to replace 
the “long-continued and indefinite duration” requirement with a 6-month 
duration requirement, Commissioner of Social Security Robert M. Ball 
explained that the bill would “drop[] the requirement that we make a 
prognosis that the disability will last for a long and indefinite period.” 
Hearings on H.R. 6675 Before the Senate Comm. on Finance, 89th Cong., 
1st Sess., Pt. I, at 153-154 (1965) (emphasis added). The people “picked up 
by” changing the “long-continued and indefinite” duration requirement to 
a six-month duration requirement, he added, would be those “whose con- 
dition is such that there is no question about the fact that they can’t work 
for [the proposed] 6 month period.” Ibid. (emphasis added). 

37 

3. a. Congress has since repeatedly reaffirmed the Com- 
missioner’s construction. Shortly after the 1965 amend- 
ments, the Commissioner issued revised criteria specifying 
that the impairment must have prevented or be expected to 
prevent the performance of substantial gainful activity 
throughout the 12-month period. See pp. 25-26 & note 7, 
supra. When Congress amended the Act in 1967 to supple- 
ment the basic definition of “disability,” it re-emphasized in 
the text of the amendment itself that the impairment must 
be of “such severity” so as to preclude the claimant from 
“engag[ing] in any * * * kind of substantial gainful work 
whic exists in the national economy.” 42 U.S.C. 423(d)(2)(A). 
And far from suggesting that Congress was unaware or 
opposed to the Commissioner’s application of that severity 
requirement when determining whether the disability has 
lasted or can be expected to last the requisite 12-month 
duration, Congress endorsed that approach: “[A]n individual 
who does substantial gainful work despite an impairment or 
impairments” that otherwise might be disabling, the Senate 
Report “reaffirm[ed],” is “not disabled for purposes of 
establishing a period of disability or for social security 
benefits based on disability during any period in which such 
work is performed.” S. Rep. No. 744, supra, at 49; S. Rep. 
No. 544, 90th Cong., 1st Sess. 31 (1967) (same). 

b. When Congress established the SSI program in Title 
XVI of the Act in 1972 to provide financial assistance to 
needy disabled persons, it incorporated the definition of 
“disability” from Title II into the SSI program. Specifically, 
acting against the settled background of the Commissioner’s 
longstanding construction of Sections 423(d)(1)(A) and 
(d)(2)(A), Congress enacted those provisions virtually verba- 
tim in Title XVI. See 42 U.S.C. 1382c(a)(3)(A) (1994 & Supp. 
V 1999); 42 U.S.C. 1382c(a)(3)(B). Just as “Congress is pre- 
sumed to be aware of an administrative or judicial interpre- 
tation of a statute and to adopt that interpretation when it 
re-enacts a statute without change,” it likewise can be pre- 

38 

sumed to have done so when it “adopts a new law incorpo- 
rating sections of [that] prior law.” Lorillard, 434 U.S. at 
580, 581. In incorporating the language of Section 423 into 
Title XVI, moreover, Congress expressly recognized that, 
under Section 423, “[n]o benefit is payable * * * unless the 
disability is expected to last (or has lasted) at least 12 con- 
secutive months.” H.R. Rep. No. 231, supra, at 56 (emphasis 
added). And it made clear that that rule “would not be 
changed” by the 1972 amendments. Ibid.; see also p. 42, 
infra (explaining further changes made by the 1972 amend- 
ments). 

c. Congress reaffirmed the Commissioner’s construction 
again in 1984. Following the 1972 amendments, the Commis- 
sioner reiterated, through a series of Social Security Rul- 
ings, the requirement that the impairment prevent or be ex- 
pected to prevent the performance of substantial gainful ac- 
tivity during the entire 12-month disability period. See, e.g., 
SSR 73-7c and SSR 82-52 (cited and quoted p. 26, supra). 
The Commissioner also incorporated the severity require- 
ment into the regulatory five-step sequential evaluation 
process. See Yuckert, 482 U.S. at 147-148. Under that five- 
step process, a claim that is adjudicated more than 12- 
months after onset of the alleged disability will be denied if 
the claimant has returned to substantial gainful activity 
within the 12-month period. See H.R. Rep. No. 618, 98th 
Cong., 2d Sess. 6-9 (1984); 20 C.F.R. 404.1520 (1982). After 
examining that process and clarifying the criteria that must 
be used in evaluating disabilities, see Social Security Dis- 
ability Benefits Reform Act of 1984, Pub. L. No. 98-460, 98 
Stat. 1794, Congress emphasized that it did not “intend to 
alter the current definition” of disability. H.R. Rep. No. 618, 
supra, at 6. To the contrary, Congress “reaffirm[ed] that the 
purpose of the disability insurance program is to provide 
benefits only for those who are unable to work.” Id. at 7; see 
also id. at 8 (“emphasiz[ing] * * * the intent of Congress 
that disability benefits should be granted to those who are 

39 

unable to work because of a medically determinable impair- 
ment”). 

4. The more than four-decade history of the definition of 
disability thus makes one thing unmistakable: Congress 
specifically contemplated the Commissioner’s construction of 
the Act, endorsed it, and reaffirmed it. In view of that his- 
tory, the Commissioner’s construction is not merely a “rea- 
sonable” or “permissible” interpretation of the Act. 
Chevron, 467 U.S. at 842-843, 844; Sullivan v. Everhart, 494 
U.S. 83, 89 (1990) (“rational and consistent with the stat- 
ute”). It is the most reasonable interpretation, and the one 
that Congress intended. 

C. The Court Of Appeals’ Construction Creates 

Precisely The Short-Term Disability Program That 
Congress Chose Not To Enact 

1. Congress created Title II’s disability insurance pro- 
gram in 1956 to fill a perceived “gap” in the Social Security 
retirement system by providing benefits to “workers who 
are forced into premature retirement” before age 65 by 
“reason of a permanent and total disability.” H.R. Rep. No. 
1189, supra, at 3 (emphasis added). Congress initially en- 
sured that the program achieved that limited goal by re- 
quiring that the disabling impairment be of long-continued 
and indefinite duration. When Congress in 1965 changed the 
duration requirement from long-continued and indefinite to 
not less than 12 months, Congress chose 12 months because 
it was a reasonable proxy for permanence. “[E]xperience 
under the disability program” between 1956 and 1965, 
Congress determined, had “demonstrated [that] in the great 
majority of cases in which total disability continues for at 
least a year the disability is essentially permanent.” S. Rep. 
No. 404, supra, at 99. Congress, in fact, rejected a shorter 
six-month period, proposed in the House of Representatives, 
because it “could result in the payment of disability benefits 
in cases of short-term, temporary disability.” Id. at 98-99. 
The Senate Report explained that, in order to prevent the 

40 

payment of benefits in cases of such temporary disabilities, it 
is “necessary to require that a worker be under a disability 
for a somewhat longer period than 6 months in order to 
qualify for disability benefits.” Ibid. (emphasis added). 

The court of appeals’ decision cannot be reconciled with 
Congress’s deliberate decision not to provide benefits “in 
cases of short-term, temporary disability.” S. Rep. No. 404, 
supra, at 99. As the court of appeals acknowledged, under 
its construction of the statutory language, no “duration re- 
quirement for the inability to engage in substantial gainful 
activity * * * exists.” Pet. App. 7a. As a result, the Com- 
missioner would have to award Title II insurance benefits to 
any claimants who are unable to work for only five months 
(the duration of the waiting period provided by 42 U.S.C. 
423(c)(2)(A)). Moreover, because Title XVI does not have a 
waiting period, the Commissioner would be required to pay 
Title XVI SSI disability benefits to claimants who suffer an 
inability to engage in substantial gainful activity of virtually 
any duration, which would create a standard of eligibility for 
benefits that is far more lenient even than the five-month 
standard that the court of appeals fashioned for Title II. The 
court of appeals nowhere explained why Congress would 
have intended such a result; nor did it explain why that re- 
sult is consistent with Congress’s repeated decision to cover 
only long-term disabilities. 

2. Perhaps recognizing that defect in the decision below, 
respondent has argued that the five-month waiting period 
provided by 42 U.S.C. 423(c)(2)(A) obviates the inconsis- 
tency between the court of appeals’ decision and Congress’s 
deliberate decision not to authorize benefits for short-term 
disabilities. See Br. in Opp. 11, 17-18. But Section 
423(c)(2)(A) hardly eliminates that conflict. For one thing, as 
we have pointed out, the waiting period applies only to Title 
II’s disability insurance program, 42 U.S.C. 401 et seq., and 
does not apply to Title XVI’s SSI program. 

41 

Even with respect to Title II, the waiting period hardly 
answers the concern. As explained above, Congress con- 
cluded in 1965 that even a six-month inability to work was 
the sort of short-term disability that should not qualify for 
benefits. See pp. 39-40, supra. For that very reason, Con- 
gress chose to require that the “worker be under a disability 
for a somewhat longer period,” namely one year. See p. 40, 
supra. That judgment by Congress refutes the court of 
appeals’ apparent assumption that the five-month waiting 
period furnishes the only protection that Congress included 
in the Act against converting the Title II disability program 
into a benefits program for short-term disabilities. 

In any event, reliance on the five-month waiting period of 
42 U.S.C. 423(c) misconstrues both the meaning and purpose 
of that provision. The waiting period provided by Section 
423(c)(2)(A) does not address whether an individual suffers 
from a “disability”—an impairment of sufficient severity and 
duration to entitle him to benefits. Instead, it provides that 
a claimant who concededly is disabled within the meaning of 
the Act nevertheless is not entitled to benefits and cannot 
receive payments for the first five months of the period of 
disability. The five-month waiting period serves three pur- 
poses. First, it helps to save public resources and to lessen 
the drain on the Trust Fund. Second, it assists in admini- 
stration by allowing the development of additional evidence; 
in some cases, Congress explained, the waiting period per- 
mits “temporary conditions to be corrected or to show defi- 
nite signs of probable recovery” before potentially inappro- 
priate payments are made. H.R. Rep. No. 1189, supra, at 6. 
Third, like a deductible on an insurance policy, it deters the 
submission of potentially insubstantial or unmeritorious 
claims. “[T]he fact that the worker frequently will be with- 
out income during [the waiting] period * * * would make it 
unprofitable for a person who could work not to do so.” Ibid. 
The waiting period thus identifies the portion of the disabil- 
ity period during which a claimant will not receive benefits 

42 

despite being disabled and unable to work. It does not spec- 
ify the length of time during which an individual must be un- 
able to engage in substantial gainful activity in order to be 
found disabled, and thus eligible for benefits, in the first 
place. 

Congress has recognized as much, and has consistently 
treated the waiting period and the disability period as dis- 
tinct. For example, when Congress shortened the waiting 
period from six months to five in 1972, the House Report 
specifically noted that altering the waiting period would not 
shorten the required duration of the disability itself. Not- 
withstanding the one-month decrease in the waiting period, 
the House Report explained, “[n]o benefit is payable * * * 
unless the disability is expected to last (or has lasted) at 
least 12 consecutive months or to result in death.” H.R. Rep. 
No. 231, supra, at 56 (emphasis added). Respondent’s at- 
tempt to treat the waiting period as a replacement for the 
duration and severity requirements cannot be reconciled 
with either the text of the Act or Congress’s manifest intent 
in enacting it. 

II. SECTION 422(c)(2) DOES NOT PROVIDE A 
“TRIAL WORK” PERIOD WHERE THE CLAIMANT 
RETURNS TO SUBSTANTIAL GAINFUL ACTIVITY 
WITHIN 12 MONTHS OF THE ALLEGED ONSET 
OF HIS DISABILITY AND BEFORE BEING 
AWARDED BENEFITS 

The court of appeals also erred in concluding that respon- 
dent was entitled to a “trial work period” under 42 U.S.C. 
422(c) when the evidence at the time his claim was adjudi- 
cated showed that he had returned to substantial gainful ac- 
tivity within 12 months of the alleged onset of his disability. 
Under Section 422(c), a beneficiary who is entitled to bene- 
fits does not lose that entitlement by performing substantial 
gainful activity during the nine-month trial work period. 
The “period of trial work shall begin with the month in which 
[the claimant] becomes entitled to disability insurance bene- 

43 

fits.” 42 U.S.C. 422(c)(3). That period ends after nine 
months of substantial gainful activity, or termination of the 
disability, whichever comes first. 42 U.S.C. 422(c)(4). “[A]ny 
services rendered by an individual during a period of trial 
work” are “deemed not to have been rendered by such indi- 
vidual in determining whether his disability has ceased in a 
month during such period.” 42 U.S.C. 422(c)(2). 

A. Reversal Of The Court Of Appeals’ Ruling Concerning 

The Necessary Duration Of The Inability To Engage 
In Substantial Gainful Activity Requires Reversal Of 
Its Ruling On The Trial Work Issue 

In this case, the court of appeals held that respondent was 
entitled to a trial work period because he became entitled to 
benefits under Title II after he was unable to engage in sub- 
stantial gainful activity during the five-month waiting pe- 
riod. “[W]hether [respondent] is entitled to a trial work pe- 
riod, in light of his return to part-time work in May 1995 and 
SGA in October 1995,” the court stated, “is conclusively set- 
tled by the determination that [respondent] was disabled 
and entitled to disability benefits” after that five-month 
period. Pet. App. 9a; see also id. at 10a (relying on the 
conclusion that respondent “was entitled to disability bene- 
fits as of April 1995”). For the reasons given in Point I 
above, however, the court of appeals erred in concluding that 
respondent was entitled to benefits merely because his 
underlying impairment lasted (or was expected to last) 12 
months. Instead, the Commissioner properly determined 
that respondent was not entitled to disability benefits be- 
cause, at the time his claim was adjudicated, his impairment 
had neither lasted nor was expected to last for the required 
minimum 12-month period at a level of severity that pre- 
cluded substantial gainful activity. For that reason alone, 
the court of appeals erred on the trial work issue. 

44 

B. In Any Event, The Court Of Appeals Erred In Its 

Interpretation Of 42 U.S.C. 422(c) And 423(d)(1)(A) 

1. Even putting that error to one side, the court of ap- 
peals’ analysis (see Pet. App. 10a-13a) fundamentally misin- 
terprets Section 422(c) and the “can be expected to last” lan- 
guage in Section 423(d)(1)(A), erroneously invalidating the 
Commissioner’s trial work regulations as a result. The 
Commissioner has consistently construed Sections 422 and 
423 as making a trial work period available only if the im- 
pairment has already precluded substantial gainful activity 
for 12 continuous months, or where there has been a deter- 
mination that it can be expected to do so. See SSR 82-52; 20 
C.F.R. 404.1592(d)(2) (as added by 65 Fed. Reg. at 42,787) 
(“You are not entitled to a trial work period” if “you perform 
work demonstrating the ability to engage in substantial 
gainful activity within 12 months of the onset * * * and be- 
fore the date of any notice of determination or decision find- 
ing that you are disabled.”). The Commissioner explained: 

Because section [422(c)] provides that a trial work period 
shall begin with the month in which a person becomes 
entitled to title II disability benefits, a claimant who does 
not become entitled to disability benefits cannot receive 
a trial work period. Under our interpretation of the du- 
ration requirement [in Section 423(d)(1)(A)], a person 
cannot be found to be under a disability if he or she per- 
forms work demonstrating the ability to perform sub- 
stantial gainful activity within 12 months after onset and 
before we have issued any notice of determination or de- 
cision finding disability. * * * On the other hand, if a 
claimant returns to work before we have made a deter- 
mination or decision finding disability, but more than 12 
months from onset, the duration requirement may be 
satisfied * * *, the claimant may become entitled to 
benefits, and the work may be protected by the trial 

45 

work period even though the work began prior to a find- 
ing of disability. 

65 Fed. Reg. at 42,774. 

That construction is fully supported by the Act’s text and 
history. The Commissioner has concluded that, when de- 
termining whether an impairment preventing substantial 
gainful activity has lasted or can be expected to last for the 
required 12-month period, the decisionmaker should consider 
all evidence available at the time of the disability determina- 
tion. See 65 Fed. Reg. at 42,780 (expectancy provision “can 
most reasonably be interpreted to mean that the time of ad- 
judication is the relevant point of reference”). 

14 Where that 

14 The Commissioner’s conclusion that the date of the adjudication is 
the appropriate point of reference would appear to be compelled by the 
statutory text. Had Congress meant for the Commissioner to determine 
whether a disability was “expected to last” 12 months at some point in the 
past based solely on evidence available at that earlier time, it would not 
have made eligibility depend on whether the disabling impairment “can be 
expected”—present tense—to last 12 months. Instead, it would have 
made eligibility depend on whether the disabling impairment “could have 
been” or “was expected” to last that long. As the Commissioner observed: 
“If Congress had intended benefits to be awarded based on evidence that 
a claimant’s impairment(s) did not in fact prevent substantial gainful 
activity for 12 continuous months, but only had been expected to do so at 
some earlier point in the 12-month period, we believe that Congress would 
have provided for a finding of disability based on an impairment(s) which 
was expected to last 12 months, in addition to one which can be expected 
to last 12 months.” 65 Fed. Reg. at 42,780. In that regard, the court of 
appeals misquoted the pertinent statutory language in its holding, since it 
declared “that a claimant whose impairment * * * which ‘lasted’ of ‘was 
expected to last’ for a continuous period of not less than twelve months 
may be disabled * * *. 42 U.S.C. § 423(d)(1)(A).” Pet. App. 8a (emphasis 
added). The statute actually uses the present tense, “can be expected,” 
not the past tense, “was expected.” 

Moreover, requiring a determination of whether the inability could 
have been expected to last twelve months at some indeterminate point 
in the past would create a significant administrative burden. Decision- 
makers would have to sift through a historical record and decide if, at 
some moment in the past, it would have been appropriate to predict that 
the inability to work would last 12 months—even if any such prediction 
would already have proven to be erroneous at the time of the adjudi- 

46 

determination takes place less than 12 months after the on- 
set of the alleged disability, and the evidence shows that the 
impairment currently prevents substantial gainful activity, 
the adjudicator must decide whether the disabling impair- 
ment “can be expected to last” for the full 12-month period, 

i.e., he must project the disability’s expected duration. If the 
adjudicator determines based on the evidence that the in- 
ability to work by reason of the impairment can be expected 
to last for at least 12 months, the individual is disabled and 
“entitled” to disability insurance benefits, and a trial work 
period then “begin[s]” with the first month in which the in- 
dividual became so entitled. 42 U.S.C. 422(c)(3). But when 
the evidence at the time the claim is adjudicated shows that 
the individual actually returned to (or became able to return 
to) substantial gainful activity within 12 months of the onset 
of the alleged disability, the adjudicator may rely on that 
evidence to conclude that the claimant’s inability to work by 
reason of his impairment already has failed to last (and thus 
cannot be “expected” to last) for at least 12 months. In such 
a situation, the claimant has at no point “become[] entitled to 
disability insurance benefits” because he has not satisfied 
the duration requirement in the statutory definition of dis- 
ability in Section 423(d)(1)(A), and the trial work period 
therefore never begins. Ibid. 

That is precisely how Congress expected the process to 
function. Explaining the statutory text at issue here—“has 
lasted or can be expected to last”—the Senate Report on the 
1965 amendments stated that, where “a worker has been un- 
der a disability which has lasted for less than 12 months, the 
bill would require only a prediction that the worker’s dis- 
ability will continue for a total of at least 12 calendar months 
after onset of the disability.” S. Rep. No. 404, supra, at 99. 
Where the “disability has existed for 12 calendar months or 

cation. Nothing in the legislative record suggests that Congress intended 
to impose such a burden on the States or the Commissioner. 

47 

more” when the claim is adjudicated, the Report further ex- 
plained, “no prognosis would be required.” Ibid. (emphasis 
added). Instead, in that situation, the Commissioner may 
rely on the claimant’s actual experience during the 12-month 
period when determining whether, at the time of the ad- 
judication, the disability has lasted or can be expected to last 
the requisite duration. Similarly, no such prognosis would be 
required if, at the time the claim is adjudicated, the evidence 
shows that the impairment no longer prevents the per- 
formance of substantial gainful activity and did not do so for 
at least 12 months. See 65 Fed. Reg. at 42,774. 

Responding to comments regarding this issue i 
the recent 

rulemaking proceeding, the Commissioner observed that 
Congress permitted the agenc to fi 
a disability “ based on 

an impairment which ‘can be expected to last’ 12 months”— 
and di 
not limit the agency to finding disability where the 

impairment had already lasted 12 months—in order “to pro- 
vide a means for [the agency] to adjudicate disability claims 
without having to wait 12 months from onset.” 65 Fed. Reg. 
at 42,774. Nothing i the phrase “has lasted or can be 
expected to last at least 12 months,” however, requires the 
Commissioner “to permit claims * * * in the face of specific 
evidence that the claimant’s impairment di not in fact 
prevent him or her from engaging in substantial gainful 
activity for 12 continuous months.” Ibid. 

2. The court of appeals’ contrary analysis is flawed. The 
court of appeals reasoned, in essence, that the Commis- 
sioner’s regulation is contrary to the statutory language be- 
cause it conditions entitlement to a trial work period on ei- 
ther a “finding of disability” or an actual inability to engage 
in substantial gainful activity for the 12-month period re- 
quired by Section 423(d)(1)(A). Pet. App. 12a. The court 
rested that conclusion on its belief that the Act provides that 
the trial work period “shall begin” once the claimant is “eli- 
gible to receive benefits.” Ibid. The court, however, mis- 
quoted the Act. The Act makes the trial work period begin 

48 

once an individual is “entitled” to benefits, not once he is 
“eligible.” See 42 U.S.C. 422(c)(1). As explained above, an 
individual who, at the time the claim is adjudicated, has suc- 
cessfully engaged in substantial gainful activity before the 
expiration of the 12-month period is not “entitled” to bene- 
fits. Where the claimant never “becomes entitled to bene- 
fits,” 42 U.S.C. 422(c)(1), the trial work period under Section 
422 never “begin[s].” 

15 

The court of appeals also thought it significant that, under 
the Commissioner’s approach, entitlement to benefits (and 
thus to a trial work period) might sometimes be affected by 
when the claim is adjudicated. For example, if an adjudica- 
tor finds a claimant disabled following seven months of in- 
ability to engage in substantial gainful activity, based on a 
prediction that the claimant’s inability to work will last at 
least an additional five months, the claimant receives bene- 
fits and a trial work period, even if the prediction later turns 
out to have been wrong and the claimant returns to work 
before the 12-month period has lapsed. In contrast, if the 
same claimant’s request for benefits is adjudicated after the 
12-month period has lapsed and the claimant successfully 
returned to work within the 12-month period, the claimant 

15 The court of appeals was also fundamentally mistaken when it stated 
that consideration of respondent’s return to substantial gainful activity, in 
determining whether respondent was disabled, “was in contravention of 
the Act.” Pet. App. 10a. Section 422(c)(2) does not prohibit consideration 
of the claimant’s substantial gainful activity when determining whether a 
disability exists in the first instance. Instead, Section 422(c)(2) states that 
substantial gainful activity, if it occurs during the trial work period, is 
deemed not to have occurred when “determining whether his disability 
has ceased in a month during such period.” 42 U.S.C. 422(c)(2) (emphasis 
added). See also H.R. Conf. Rep. No. 964, 101st Cong., 2d Sess. 939 (1990) 
(“During this period, disabled beneficiaries may test their ability to work 
without affecting their entitlement to disability benefits. Any work and 
earnings are disregarded in determining whether the beneficiary’s dis- 
ability has ceased.”). Section 422 thus addresses determinations of 
whether a disability has ceased, not whether the requirements for an 
initial finding of disability have been met. 

49 

would not be entitled to receive benefits or a trial work pe- 
riod. 

As the Commissioner has explained, “the relatively infre- 
quent, but regrettable, occasions in which” the timing of the 
adjudication affects the outcome are a “necessary” conse- 
quence of permitting the “SSA to adjudicate disability claims 
and award benefits without having to wait 12 months from 
onset,” as well as the necessity of relying on potentially 
faulty predictions about an impairment’s duration when do- 
ing so. 65 Fed. Reg. at 42,780. Simply put, the fact that 
some individuals may be awarded benefits (and trial work 
periods) based on predictions about the duration of their in- 
ability to engage in substantial gainful activity that turn out 
to have been incorrect in no way compels the Commissioner 
to award benefits to those individuals who, based on all the 
available evidence, clearly are not entitled to receive them. 
Certainly nothing in the Act compels the Commissioner to 
ignore evidence proving that the claimant’s inability to en- 
gage in substantial gainful activity in fact did not last (and 
thus cannot be expected to last) the requisite period of time. 

The court of appeals, however, appeared to suggest that 
the decisionmaker must ignore such proof and award bene- 
fits where, for example, the adjudicator knows that the 
claimant successfully returned to work before the 12-month 
period expired. There is no basis for reading such an exclu- 
sionary rule into the Act. In other legal contexts, evidence 
that develops after a claim is filed, but before it is adjudi- 
cated, is admissible even though the result may be that out- 
comes depend on when the adjudication takes place. For ex- 
ample, a plaintiff suing in tort for lost prospective wages will 
recover less if, after he is injured but before trial, he returns 
to work and thereby conclusively demonstrates that his 
earning capacity was not so greatly diminished as originally 
claimed. No one suggests that a jury would be precluded 
from taking such post-claim/pre-trial conduct into account 
merely because the evidence would not have been available 

50 

had the trial taken place earlier. Similarly here, there is no 
reason why the Commissioner should be barred from taking 
an applicant’s post-claim return to work into account, where 
it bears directly on whether his inability to engage in sub- 
stantial gainful activity by reason of the impairment has 
lasted (or can be expected to last) for at least 12 months. 

16 

CONCLUSION 

The judgment of the court of appeals should be reversed. 

Respectfully submitted. 

THEODORE B. OLSON 

Solicitor General 

ROBERT D. MCCALLUM, JR. 

Assistant Attorney General 

EDWIN S. KNEEDLER 

Deputy Solicitor General 

JEFFREY A. LAMKEN 

Assistant to the Solicitor 

General 

JOHN C. HOYLE 
MARK S. DAVIES 

Attorneys 

NOVEMBER 2001 

16 The court of appeals’ other reasons for rejecting the Commissioner’s 
interpretation of the “can be expected to last” language in Section 
423(d)(1)(A) also lack merit. First, the court rejected that interpretation 
because the Act does not explicitly mention adjudication as a prerequisite 
to a finding of disability. Pet. App. 13a. But the Act does permit a finding 
of disability when the impairment preventing substantial gainful activity 
“can be expected” to last 12 months. The Commissioner reasonably con- 
cluded that the relevant expectation is that of the decisionmaker, on the 
basis of the evidence available at the time of the disability determination. 
See p. 45 & note 14, supra. Second, the court observed that no other part 
of the Act “differentiates between claims adjudicated within twelve 
months, and claims adjudicated after twelve months.” Ibid. But no other 
part of the Act contains similar statutory language regarding expectan- 
cies.