                            In the
 United States Court of Appeals
              For the Seventh Circuit
                        ____________

No. 05-3773
GARY ALLORD,
                                              Plaintiff-Appellant,
                               v.

JO ANNE B. BARNHART, Commissioner
of Social Security,
                                             Defendant-Appellee.
                        ____________
           Appeal from the United States District Court
               for the Western District of Wisconsin.
          No. 04-C-0738-C—Barbara B. Crabb, Chief Judge.
                        ____________
       ARGUED JULY 11, 2006—DECIDED AUGUST 4, 2006
                        ____________


  Before BAUER, POSNER, and KANNE, Circuit Judges.
  POSNER, Circuit Judge. Gary Allord is embarked on a
quest, thus far unsuccessful, for social security disability
benefits. He is a decorated Vietnam combat veteran con-
ceded to be suffering from severe post-traumatic
stress disorder, but because he lost social security coverage
in 1992 he cannot obtain benefits unless he proves that his
PTSD was disabling then, as it is now.
  He was honorably discharged from the Marine Corps in
1987 and had difficulty adjusting to civilian life; he was also
2                                                 No. 05-3773

getting divorced. A woman who had known him since 1982,
Melissa Chappell-White, observed his condition and
suggested that he consult a psychologist whom she knew,
Dr. Foster Hutchinson, and he did so; this was in 1987,
shortly after his discharge. Dr. Hutchinson, in his notes of
the consultation, described Allord as pleasant, controlled,
and articulate, though sad, and diagnosed him as suffering
from an “adjustment disorder with depressed mood” and
“compulsive personality disorder” and recommended that
he undergo weekly therapy; Allord declined. But in
1993—four months after his social security coverage
lapsed—he consulted a psychologist at a veterans’ medical
center, Aphrodite Matsakis. A specialist in PTSD, she
diagnosed Allord’s condition as severe and chronic PTSD.
Again he declined treatment, this time until 1996. But
between then and 1999 he received 200 hours of therapy
from Dr. Matsakis.
  In 1997, the Department of Veterans Affairs determined
that Allord was 100 percent disabled by PTSD. Determina-
tions of disability by other agencies do not bind the Social
Security Administration, however, 20 C.F.R. § 416.904, and
anyway the Department of Veterans Affairs requires less
proof of disability than the Social Security Administration
does. Compare Ortiz v. Principi, 274 F.3d 1361, 1364 (Fed.
Cir. 2001), with Jones ex rel. Jones v. Chater, 101 F.3d 509,
512 (7th Cir. 1996). We have said that SSA should give
the VA’s determination of disability “some weight.” Davel
v. Sullivan, 902 F.2d 559, 560-61 n. 1 (7th Cir. 1990). The
Ninth Circuit says “great weight,” McCartey v. Massanari,
298 F.3d 1072, 1075-76 (9th Cir. 2002), but this disregards the
substantial difference between the criteria used in the two
programs. The administrative law judge gave the VA’s
determination that Allord was disabled no weight because
the determination had been made almost four years after
No. 05-3773                                                3

Allord had lost coverage. The judge should have given the
VA’s determination some weight, in light of the evidence
we discuss below that Allord’s PTSD was of long standing.
  At Allord’s hearing before the administrative law judge,
Dr. Matsakis opined that Allord had begun having symp-
toms of PTSD in the early 1970s, and that by 1987 (six years
before his coverage expired) he was totally disabled from
gainful employment. She described his condition as follows:
    [I]f you run down the criteria for post traumatic stress,
    they are all there. The hyper alertness, the constant
    vigilance. The fact that he was startled and almost ready
    to assault an old lady who he cherished…. He’s trig-
    gered by everything. The fact that he’s dissociating,
    memory problems…. The fears he has about being
    with people. The anger, the distrust, the state of para-
    noia, the withdrawal. If he’s successful at anything,
    at the teeniest hint, which he doesn’t even dream of
    that, even if he was he would be frightened because of
    triggers, which we don’t have time to go into which
    would take probably a year to explain. But basically
    anything that anyone does will set him off. Being in a
    closed room will set him off, being in open spaces.
    Noise sets him off. Silence sets him off. Kindness sets
    him off. Hostility sets him off and sends him off into
    either no man’s land where he can’t think or you see
    that angry look in his eye and he’s doing everything
    to control it. If the scratches and bruises I’ve seen on
    him a couple times are evidence that he sometimes can’t
    control himself…. The only work he does is staying
    alive, which is amazing that he’s even here. No he can’t
    do anything.
Another psychologist specializing in PTSD, also employed
by the Department of Veterans Affairs, Jonathan Shay,
4                                                  No. 05-3773

seconded Matsakis’s testimony on the basis of an evaluation
of Allord that Dr. Shay conducted in 1997.
  Chappell-White testified that she had observed Allord’s
mental deterioration during the 1980s; that he could not
communicate, could not carry out instructions (he did some
handyman work for her), and failed to show up for work on
a regular basis. Her testimony was important because
neither Dr. Matsakis nor Dr. Shay had observed Allord in
the critical period, that is, before his coverage lapsed. Not
that Chappell-White’s testimony by itself established that
Allord was totally disabled; but it supported the psycholo-
gists’ belief that Allord’s disabling PTSD was of long
standing.
   The administrative law judge disbelieved Chappell-
White’s testimony, however, and ordinarily a trier of
fact’s credibility finding is binding on an appellate tribunal.
But not if the finding is based on errors of fact or logic. E.g.,
Hanaj v. Gonzales, 446 F.3d 694, 700 (7th Cir. 2006); Georgis v.
Ashcroft, 328 F.3d 962, 970 (7th Cir. 2003); Cao He Lin v. U.S.
Dept. of Justice, 428 F.3d 391, 403 (2d Cir. 2005). The adminis-
trative law judge said that a lay witness’s testimony about
the mental illness of an acquaintance cannot be believed
unless the witness acted on her observation, as by referring
the acquaintance for a psychiatric examination. The premise
is dubious, to say the least, but in any event Chappell-White
did act on her observation—she referred Allord to Dr.
Hutchinson. The administrative law judge also reasoned
that if Chappell-White had thought Allord unable to work,
she wouldn’t have recommended him to people who
needed the kind of work he did. But her unchallenged
testimony was that she made no such recommendations.
The administrative law judge further disbelieved her
testimony because she’d been friendly with Allord (there is
No. 05-3773                                                  5

no suggestion, by the way, of any romantic attachment). But
a friend would be more likely than a stranger to observe
symptoms of mental illness, yet less likely to refer the
mentally ill person to a psychologist on frivolous grounds;
one doesn’t casually conclude that one’s friends are men-
tally ill.
   The government argues that these errors were harmless
because the administrative law judge could have discredited
Chappell-White’s testimony on other grounds, for example
its apparent inconsistency with Dr. Hutchinson’s contempo-
raneous evaluation of Allord’s condition. The argument
misunderstands the nature of a credibility determination.
Such a determination is a judgment call based on whatever
circumstances bear on a witness’s credibility. The adminis-
trative law judge based his judgment call on a variety of
considerations but three of them were mistaken. Whether he
would have made the same determination had he not erred
in these respects is speculative.
  The only situations in which an error in the factors
considered by the trier of fact in making a credibility
determination can confidently be thought harmless are
when a contrary determination would have to be set
aside as incredible or when the trier of fact says that he
would have made the same determination even if the
questioned circumstances had been different from what he
thought them to be and he gives an adequate reason for that
back-up position. In either of those situations it would be
inconceivable for the trier of fact to have made a different
finding on credibility, Frank v. Barnhart, 326 F.3d 618, 621-22
(5th Cir. 2003), and if so the finding stands despite the flaws
in his analysis.
 So only if no reasonable trier of fact could have believed
Chappell-White’s testimony (for example, if she’d testified
6                                                 No. 05-3773

that she had first met Allord before she was born), or if the
administrative law judge had said that even if Chappell-
White had acted on her observations of Allord’s mental
condition, had not referred him for work to other people,
and had not been a friend, he would have disbelieved
her for sufficient other reasons, would the errors that we
have identified have been harmless. Neither condition is
satisfied.
   The administrative law judge rejected Dr. Matsakis’s
opinion regarding Allord’s condition in the critical period
on the ground that there must be contemporaneous medical
evidence of the applicant’s condition. We said in Wilder v.
Apfel, 153 F.3d 799, 802 (7th Cir. 1998) (emphasis in original)
that “what is required [to establish a retrospective diagno-
sis] is contemporaneous corroboration [contemporaneous
with the period of coverage, that is] of the mental
illness, . . . not necessarily contemporaneous medical
corroboration.” “Retrospective diagnosis of an impair-
ment, even if uncorroborated by contemporaneous med-
ical records, but corroborated by lay evidence relating
back to the claimed period of disability, can support a
finding of past impairment.” Newell v. Commissioner of Social
Security, 347 F.3d 541, 547 (3d Cir. 2003); see also Loza v.
Apfel, 219 F.3d 378, 396 (5th Cir. 2000). Contemporaneous
corroboration was provided in this case by Chappell-White,
whose testimony the administrative law judge, as we have
just seen, improperly discredited.
  Moreover, contemporaneous corroboration is not always
required—just usually. Likes v. Callahan, 112 F.3d 189, 191
(5th Cir. 1997); Jones v. Chater, 65 F.3d 102, 104 (8th Cir.
1995). A disease might have a well-understood progression,
so that a physician examining a patient at time t might have
a good idea of what the patient’s condition was at time t - n,
No. 05-3773                                                 7

where n was the number of years, prior to the examination,
by which time the patient could have had to be completely
disabled to be entitled to benefits. But that will be an issue
in this case only if, on remand, the administrative law judge
determines once again, but this time on acceptable grounds,
that Chappell-White is not a credible witness.
  The administrative law judge also gave too much
weight to Dr. Hutchinson’s 1987 description of Allord’s
condition. Hutchinson’s examination of Allord was much
farther in time from the critical date on which Allord’s
social security coverage ended than Dr. Matsakis’s—more
than five years versus four months. More important,
Matsakis is an expert in PTSD; Hutchinson, so far as
appears, is not. Apparently in the 1980s, when Hutchinson
examined Allord, the condition was not yet well under-
stood. See Matthew J. Friedman, “Posttraumatic Stress
Disorder: An Overview,” July 20, 2006 (Dept. of Veterans
Affairs, National Center for PTSD), http://www.
ncptsd.va.gov/facts/general/fs_overview.html. If Hutchin-
son was not familiar with it, his failure to diagnose it in
Allord would have little if any significance. The administra-
tive law judge missed this point too.
  Whether Allord is entitled to benefits remains to be
determined. The evidence on which he relies contains
infirmities; these include discrepancies between Dr.
Matsakis’s 1993 intake notes when she first examined Allord
and her diagnosis and testimony based on her treatment of
him that began in 1996. But the flaws in the administrative
law judge’s reasoning are too serious to allow us to uphold
the Social Security Administration’s decision. The case must
be returned to the Administration for further proceedings
consistent with this opinion.
                                 REVERSED AND REMANDED.
8                                            No. 05-3773

A true Copy:
       Teste:

                      _____________________________
                       Clerk of the United States Court of
                         Appeals for the Seventh Circuit




                USCA-02-C-0072—8-4-06
