MEMORANDUM OPINION AND ORDER
Howard Hughes (“Hughes”) appeals the final decision of Commissioner of Social Security Shirley Chater (“Commissioner”) denying Hughes’ claims for disability insurance benefits under the Social Security Act (“Act”), 42 U.S.C. §§ 416(i) and 423.2 Fifty-five-year-old Hughes suffers from severe arthritis. At issue is the date upon which his arthritis and other maladies so hindered his activities that they rose to the level of a disability under the Act. Now claiming a February 7,1991 onset date,3 Hughes argues that he is entitled to disability benefits because he was in fact disabled before his insured status lapsed on March 31, 1991 (see Reg. §§ 404.130-132) (R. 103).4
As is usual in such cases, Hughes and Commissioner have filed cross-motions for summary judgment under Rule 56, with Hughes moving alternatively for a remand. For the reasons stated in this memorandum opinion and order, the cross-motions are denied and Hughes’ motion for a remand is granted.
Background5
Hughes stands about 6 feet tall and weighed about 137 pounds at the time of the Hearing, though his “original” weight was 160 (R. 43). He has never been married, has no children and rents a room in his aunt’s home (R. 44^45). Hughes has no vocational or specialized job training (R. 48) — having quit school after the 11th grade, Hughes completed his GED in 1979 while incarcerat*987ed for armed robbery (R. 47-48, 55). During that same term of imprisonment Hughes first hurt his back when he was “lifting some iron” (R. 56). He was hospitalized for 3 days (R. 56-57).
Though Hughes had earlier employment, the ALJ asked that he focus only on the 15-year period before the Hearing (R. 54). In 1982 Hughes worked on an assembly line for 6 to 8 months (R. 51-54), a job that involved some sitting, walking and standing (R. 52). When he acted as a runner delivering “various objects” to “various places” in the company, those objects ranged from 3 to 30 pounds, though most weighed less than 10 pounds (R. 53). During Hughes’ tenure in that position he entered the hospital for a foot operation, but when he returned to work he found that he was fired (R. 51-52).
From 1984 to 1989 Hughes worked as a porter in the commissary at Chicago Stadium (R. 49-50). There his responsibilities included manually hauling kegs of beer up staircases about 3 days a week (R. 50). He also handled boxes of stock of different weights, but enlisted the aid of a dolly when moving them to storage (R. 51).
Between jobs Hughes spent much of his tíme in prison. From 1959 to 1964 he had been imprisoned for possession of cannabis and violation of probation (R. 54). In 1965 he returned to prison to serve 2 more years for possession of cannabis (R. 55). From 1970 to 1974 he was incarcerated for robbery (id), only to return to prison later in 1974 to serve a 5-year sentence on an armed robbery conviction (id). Hughes also spent approximately 10 months of 1990 in prison for burglary (R. 56).
As if to emulate (at least in some respects) the eccentric billionaire of the same name, on a typical day Hughes mostly sleeps, reads or watches television (R. 64).6 He usually stays in his house but takes an occasional 2-block walk on warm days (R. 64, 72).
Medical Evidence
Hughes’ Testimony
Hughes complains of a deteriorated right triceps, pain in his spine and swelling in his left hand and shoulder (R. 59). He has arthritic pain in both hips, his neck and both shoulders (id). His legs, feet and one knee were swollen and numb at the Hearing (id). He also suffers from a slight nervous disorder that he refers to as muscular sclerosis, which originated when he was hit by a truck a long time ago (id.).
Hughes’ pain from all these maladies has gradually worsened over the years (R. 63) so that he can only sleep about % hours each night (R. 68) and walk with the aid of a cane (R. 65-66). Hughes soaks in the tub about 4 times a week to ease his pain temporarily, but he usually just tries to sleep through it (R. 70). When asked which of his ailments bothered him the most, Hughes responded “all of them” (R. 59) .7
When asked about the genesis of his pain, Hughes first noted that he had been shot twice, once in his left thigh in 1965 and once in his back in 1980 (R. 60). When doctors mended his leg they “tied up a nerve in there,” resulting in discomfort when the leg swells (R. 61). To correct a condition that he referred to as “hammer toes,”8 Hughes also underwent surgery that involved the insertion of metal plates in both feet (R. 61-62). His last hospital stay was during 1980, when he received treatment for a blow to the head sustained during a robbery attempt (Hughes *988was the victim) (R. 62). His speech was slurred for about a month, and he continues to suffer frequent headaches (R. 63).
During the Hearing the ALJ attempted to establish the point at which Hughes’ respective maladies became disabling. Here is what Hughes had to say (R. 63-65):
Q: When did they get real bad?
A: Well, they got real bad last year, after I, I came to, down here the last time, when I talked to this, this doctor, what’s his name?
# * ‡ ‡ ‡
A: Yeah and it just got worse since then, I got sick, I suffer tremendously....
Q: How bad did your condition get back, get bad after July, ’92?
A: It got real bad, it’s real, it’s hard for me to sleep, you know what I’m saying, sometimes I try to sit up and sometime I can’t lay down, sometime I have to stretch across the table like this, lean forward, with seven or eight pillows up there because the pain is tremendous all up in here and in here and I get numb. This is the reason for, for the blood circulation pills, Tritol (phonetic), that they gave me.
Q: Were your activities better before July, ’92, could you do more things and get around better and that?
A: Yeah, I could get around a little bit better but now, I don’t, I don’t hardly get around none, I be in the house most of the time. Weather like this here, if I didn’t have to come down here, I would be in right now and I mostly sleep, I may watch television for about a hour or so or try to read, other than that, I be asleep, take a walk every now and then for maybe about two blocks at the most.
Q: Now, we don’t have any medical reports from about, I guess about March of ’91, that was Dr. Kaplan, to about August of ’93, were you doing pretty good during that period, is that why you—
A: When?
Q: March of ’91 to August of ’93?
A: Well now—
Atty: August of ’93? This is Dr.—
ALJ: Yeah, right, I’m sorry, August of ’92.
A: ’92 I was hurting.
Q: Huh?
A: ’92 I was hurting real bad but I, ’91 I was hurting but I wasn’t hurting in ’91 like I was in ’92 up to now.
Q: And that’s why you didn’t see a doctor.
A: Yeah and Dr. Kaplan is no longer at that place no more, Stone Island, in fact he quit the place there, where he was doctor at the medical center.
Q: And then you starting seeing a doctor in August of ’92 because your condition was getting real bad.
A: Yeah, worse, worse, it got worse.
Because of his pain Hughes can only stand for 5 or 10 minutes at a time (R. 74). He is able to take care of his personal needs such as washing, shaving and dressing with some difficulty and pain (R. 70). He is unable to do any housework, cooking, laundry or lawn work, and he can lift only about 10 pounds (R. 71, 75). He smokes about 3 or 4 cigarettes a day but has not used drugs or alcohol since 1991 (R. 57, 71).
Formal Evaluations
Physical Impairments
According to the exhibits presented at the Hearing, Dr. Robert Kaplan treated Hughes from December 12, 1990 until March 6, 1991 (R. 2).9 Dr. Kaplan’s records refer to a December 12, 1990 x-ray interpreted this way by Dr. Narain Sawlani (R. 125, 126):
VIEWS OF THE LUMBAESACRAL SPINE; DEGENERATIVE CHANGES WITH OSTEOPHYTE FORMATION.10 *989THERE IS MARKED NARROWING OF THE DISC SPACE BETWEEN L1-L2 AND L2-L3. POSSIBILITY OF OLD TRAUMA IN THIS AREA SHOULD BE CLINICALLY CONSIDERED. POSSIBILITY OF NARROWING OF THE DISC SPACE BETWEEN L5-S1 CAN NOT BE RULED OUT. NEGATIVE FOR SPONDYLOLISTHESIS.11
IMPRESSION:
DEGENERATIVE CHANGES LUM-BARSACRAL SPINE MORE MARKED IN THE UPPER LUMBAR AREA. POSSIBILITY OF OLD TRAUMA IN THIS AREA SHOULD BE CLINICALLY CONSIDERED.
ADVISE CLINICAL CORRELATION.
On January 29,1991 Dr. Kaplan noted on a “Certificate to Return to School or Work” that Hughes was not able to return to work due to “arthritis in the lumbo-sacral spine, feet, etc.” (R. 124). Just over a month later, on March 6, 1991, Dr. Kaplan again examined Hughes and filled out an extensive Arthritic Report, noting that Hughes suffered from “osteo-arthritis12 LS-spine with narrowed disc spaces at Ll-2, L2-3, L5-S1,” from disc and bone degeneration and from spasms in the paraspinal muscles (R. 126). There was also evidence of “cervical and/or lumbar nerve root compression or peripheral neuropathy” (R. 128). Nevertheless Dr. Kaplan concluded that Hughes’ ambulation was normal (R. 127), that he exhibited no abnormal weakness (id.) and that his mental status was “essentially normal” (R. 128).
When Hughes submitted his application for disability insurance benefits in February 1991, he was interviewed by an SSA interviewer, who noted that the “claimant walks as though he can not stand straight up” but also observed that his “appearance and behavior were normal” (R. 112). On March 19, 1991 Dr. E.C. Bone completed a Residual Physical Functional Capacity [“RFC”] Assessment of Hughes (R. 129-136), finding that Hughes suffered from osteoarthritis, narrowed disc spaces and muscle spasms (R. 130). Nevertheless Dr. Bone concluded that Hughes was capable of (R. 130):
Lifting/carrying 25 lbs: Frequently
Lifting/carrying 50 lbs: OccasionaUy
Standingy'waikmg in 8 hr. About 6 hours workday:
Sitting in 8 hr. workday: About 6 hours
Push and pull: Unlimited except as already noted
On the next day a vocational assessment specialist reviewed Hughes’ application and concluded that he was not disabled because he could still perform several jobs requiring only light work (R. 113). Then on March 28 Dr. Eugene Wenthe signed a Social Security Administration Disability Determination and Transmittal stating that while Hughes suffered from “osteoarthritis of LS Spine,” he was not disabled (R. 122).
Hughes next filed for reconsideration of his application. On July 2, 1991 he met again with the same SSA interviewer who had completed the first report. During that second interview Hughes had no difficulty in walking, though he still did not “stand up straight” (R. 118). On July 22, 1991 Dr. Charles Kenney completed another RFC Assessment (R. 137-44), reaching conclusions identical to those of Dr. Bone. On July 31, 1991 Dr. Bone reaffirmed his original determination that Hughes was not disabled (R. 123).13
ALJ Sprague noted during the Hearing that there was a gap in the medical reports *990between March 1991 and August 1992 (R. 64-65), when Hughes’ general medical condition began to be reviewed on a monthly basis beginning August 11,1992 and ending May 3, 1993 (R. 201-03). While those latter reports are unsigned, Hughes’ testimony as to the dates of his treatment (R. 64-65) and the medications prescribed by Dr. V.W. Steward (R. 69) suggest that the notes were recorded by Dr. Steward. Under Dr. Steward’s care Hughes’ weight fluctuated from 129 to 145 pounds, but there is no mention of spinal abnormality or arthritis until May 3, 1993, when Dr. Steward ordered a shoulder x-ray (R. 203). Dr. Sawlani reviewed that x-ray and concluded (R. 200):
VIEWS OF THE LEFT SHOULDER; DEGENERATIVE CHANGES ARE NOTED IN THE VISUALIZED ACRO-MIOCLAVICULAR JOINT WITH SCLEROSIS AND OSTEOPHYTE FORMATION. NO OTHER SIGNIFICANT VISUALIZED BONY ABNORMALITY DEMONSTRATED.
ADVISE CLINICAL CORELATION [sic].
Dr. Steward also completed a Physical Capacities Evaluation Form for Hughes on May 2, 1992 in which he found that Hughes was limited to (R. 150-51):
Lifting 21-25 lbs: Occasionally
Lifting 26-50 lbs: Never
Stand in 8 hr. workday: 1 hour
Walk in 8 hr. workday: 1 hour
Sit in 8 hr. workday: 2 hour
Push and pull: Unlimited except as already noted
Hughes could not climb at all and could only occasionally bend, squat and crawl (R. 151).
Dr. Jordon Traflmow completed a consultative report on Hughes that was later considered at the Hearing. On July 23,1992 Dr. Traflmow found that x-rays of the lumbar spine were normal and that joint spaces were well maintained (R. 177). Cervical spine x-rays were also “basically normal” except for some narrowing of the joint spaces and some osteophytes at C6-C7, C5-C6 and C4-C5 (id). During the examination Hughes claimed that he could not bend, but he was able to bend while getting into a chair (R. 176). Hughes also claimed that he could not raise his arms past 45° of elevation, yet proceeded to put his arms over his head to remove his shirt (R. 176-77). Finally, while Hughes claimed that he could flex his spine only about 40°, he flexed to 90° with no difficulty when getting out of the chair (R. 177). In sum, Dr. Traflmow was “unable to find any objective evidence of the reasons for the claimant’s pain” (R. 178), though he noted that Hughes could only “stand and/or walk” for 4 hours in an 8-hour day (R. 180).
Toward the end of the Hearing, Hughes’ attorney suggested that an updated consultative evaluation complete with new x-rays be ordered to supplement the record. Dr. Leonard Smith conducted that updated evaluation ordered by the ALJ on January 11, 1994 (R. 204-08). Hughes’ gait was then normal (R. 205). Dr. Smith examined Hughes’ lumbar spine and found that Hughes was a “well-developed, well-nourished male in no acute distress” (R. 204). But roentge-nograms taken of the lumbar spine revealed degenerative disc disease at L5-S1, narrowing of the disc space and “rather marked degenerative changes throughout the lumbar spine” (R. 206). Moderate scoliosis was also noted (id.). Compression tests on the cervical spine were also normal, though Dr. Smith noted subjective tenderness in the left tra-pezius area (R. 205). One joint in Hughes’ left shoulder was found to have undergone degenerative changes, and there was atrophy in his right upper arm due to an old injury (R. 205-06). Atrophy in his right hand was also evident, and the thumb on his left hand exhibited some thickening and degenerative changes (R. 205). Dr. Smith concluded that Hughes is “an asthenic individual, who is apparently in a poor nutritional status” (R. 206). He found that in an 8-hour day Hughes could (R. 207-08):
Lift/carry 10 lbs: Occasionally
Lift/carry 5 lbs: Frequently
Stand/walk: 5-6 hours (1-2 without interruption)
Sit: Unlimited
Hughes could also occasionally kneel, crouch and stoop, and he could push and pull up to 5 to 10 pounds (R. 208).
Mental Impairments
Hughes was examined before the Hearing (on June 19, 1992) by psychologist Norman Kerr (“Kerr”), Ph.D., A.B.P.P. Dr. Kerr administered a battery of psychological tests *991to Hughes and summarized his findings in a 5-page report (R. 155-59). Dr. Kerr found that Hughes “was mentally oriented to time and place and in contact with reality” (R. 157). Dr. Kerr also found that Hughes’ verbal abilities “significantly exceed his performance skills,” though Dr. Kerr said “it is possible that his deficiencies in [the nonverbal] area stem from his arthritic condition in his hands, arms and fingers” (R. 158). Dr. Kerr concluded (R. 158-59):
Psychodiagnostieally, Mr. Hughes, age 52, has a pervasive and enduring pattern of antisocial behavior beginning in early adolescence and continuing into adulthood although less obvious since reaching middle age. This antisocial personality disorder has been characterized by the onset of a conduct disorder in early adolescence with subsequent failures to conform to social norms with respect to lawful behavior during adulthood. Associated with the foregoing has been a heavy and prolonged substance abuse disorder. While these two chronic disorders now appear to be ameliorated due probably to the effects of medical treatment, periods of forced confinement and advancing age, he has nevertheless not regained his premorbid health status because of co-existing non-mental impairments. For the foregoing reason, it is the examiner’s opinion that he has not achieved an adequate level of adaptation that is required to engage in sustained gainful work activity....
Dr. Kerr’s conclusions are echoed in his Mental RFC Evaluation of Hughes (R. 160-63). According to that evaluation Hughes’ impairment will seriously affect virtually every aspect of his life from his daily living activities to his ability to understand complex instructions and interact appropriately with supervisors (R. 161-62). Dr. Kerr sums up Hughes’ limitations by stating (R. 162):
The patient’s non-mental disabilities will impact on his mental status resulting in decomposition if placed in a competitive stressful work situation.
At the Hearing Dr. Benjamin Blackman, a psychiatrist serving as the medical consultant to the ALJ, testified that he had reviewed the psychological test data gathered by Dr. Kerr and disagreed with the latter’s conclusions (R. 81):
[F]rom a mental point of view, the test does not indicate limitations, other than perhaps the claimant would have difficulty with complex tasks because of his low normal IQ, his full-scale IQ was 81. And from his testimony this morning, the entire testimony revolved around physical problems, I was not able to discern that he would have any work-related limitations from (INAUDIBLE).
Dr. Blackman also disagreed with Dr. Kerr’s conclusion that Hughes would have difficulty interacting with supervisors and their demands in a competitive workplace. According to Dr. Blackman, Hughes had simply chosen not to exercise his ability to interact well (R. 85).
Statutory and Regulatory Framework
Under Section 423(a)(1) a person is eligible for disability benefits if he or she:
(A) is insured for disability insurance benefits ...,
(B) has not attained retirement age ...,
(C) has filed application for disability insurance benefits, and
(D) is under a disability....
“Disability” is defined in pertinent part as the inability (Section 423(d)(1)(A)):
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 expected to last for a continuous period of not less than 12 months....
Wolfe v. Shalala, 997 F.2d 321, 322-23 (7th Cir.1993) (citations omitted) recites the familiar 5-step process that guides Commissioner’s sequential evaluation of a disability claim:
In determining disability, the ALJ was required to address each of the following questions in sequential order: (1) Is the claimant presently employed? (2) Is the claimant’s impairment or combination of impairments severe? (3) Do his or her impairments meet or exceed any of the specific impairments listed in 20 C.F.R. Pt. *992404, Subpt. P., App. 1 which the Secretary acknowledges to be conclusively disabling? (4) Have the claimant’s impairments limited his or her remaining or “residual” functional capacity to the point that he or she is no longer able to perform the demands and duties of a former occupation? (5) Is the claimant unable to perform any other work in the national economy given his or her age, education and work experience?
A negative conclusion at any step (except for step three) precludes a finding of disability. An affirmative answer at steps one, two or four leads to the next step. An affirmative answer at step three or five results in a finding of disability.
See also Knight v. Chater, 55 F.3d 309, 313 (7th Cir.1995). In that process it is generally the claimant’s burden to establish that he or she became disabled on or before the date last insured (Meredith v. Bowen, 833 F.2d 650, 652 n. 1 (7th Cir.1987)).
At step 4 a claimant will be deemed “not disabled” if he or she can perform either (Wolfe, 997 F.2d at 323, quoting SSR 82-61 (emphasis in original)):
1. The actual functional demands and job duties of a particular past relevant14 job; or
2. The functional demands and job duties of the occupation as generally required by employers throughout the national economy.
And where a claimant’s assertions of pain are at issue, Herron v. Shalala, 19 F.3d 329, 334 (7th Cir.1994) (citations omitted) teaches:
Once the presence of a medically determinable physical or mental impairment is established that could reasonably be expected to produce the pain alleged, but the intensity or persistence of the pain is unsubstantiated by the medical record, the ALJ is obliged to examine and weigh all the evidence including observations by treating and examining physicians, third-party testimony, the claimant’s testimony and daily activities, functional restrictions, pain medication taken, and aggravating or precipitating factors to evaluate how much the claimant’s impairment affects his ability to work.
Procedural History and Administrative Findings
As stated earlier, Hughes applied for disability insurance benefits on February 7, 1991 (R. 93). That application was initially denied on April 4, 1991 (R. 96-98) because he was found capable of performing “a limited range of medium work” (R. 96). Hughes filed a Request for Reconsideration (R. 99), which was also denied (P.Mem. 1).
Next Hughes requested (R. 90) and was afforded the Hearing pursuant to Section 405(b). That resulted in ALJ Sprague’s denial of Hughes’ application because of his failure to demonstrate that he was incapable of performing any of his past jobs on or before March 31, 1991 (a step 4 determination) (R. 19). ALJ Sprague’s opinion included these findings (R. 20-21):
2. The medical evidence establishes that the claimant has severe generalized arthritis, substance abuse in remission, and a mild personality disorder, but that he does ' not have an impairment or combination of impairments listed in, or medically equal to one listed in Appendix 1, Subpart P, Regulations No. 4.
3. Since about October 1, 1992, many of the claimant’s complaints have been supported by the medical evidence.
4. Since October 1,1992, the claimant has been limited in performing sustained walking or standing, or lifting occasionally more than 10 pounds.
5. Since October 1,1992, the claimant has been unable to perform his past relevant work as a porter or assembler. Prior to October 1,1992, he could perform his past relevant work.
6. Since October 1,1992, the claimant has had the residual functional capacity to per*993form the full range of sedentary work (20 CFR 416.967).
* * s}: # *
10. Section 416.969 of Regulations No. 16 and Rule 201.12, Table No. 1, Appendix 2, Subpart P, Regulations No. 4, direct that the claimant, considering his residual functional capacity, age, education, and work experience, be found “disabled”.
11. The claimant has been under a “disability” as defined in the Social Security Act, since October 1, 1992, but not before (20 CFR 416.920(f)).
On September 22, 1994 the Appeals Council denied review of ALJ Sprague’s decision (R. 6-7). That decision thus became Commissioner’s final decision (Reg. § 404.981; Diaz v. Chater, 55 F.3d 300, 305 n. 1 (7th Cir.1995.)).
Standard of Review
Section 405(g) empowers this Court to affirm, modify or reverse Commissioner’s decision with or without remand for rehearing. When such a review deals with the proper construction of the governing statute and regulations, it presents a question of law that is reviewed de novo (Dotson v. Shalala, 1 F.3d 571, 575 (7th Cir.1993)). By contrast, Diaz, 55 F.3d at 305-06 (citations omitted, and adapted to this case) sets out the standard of factual review:
Our review of the SSA’s decision is limited. 42 U.S.C. § 405(g) (“The findings of the Secretary as to any fact, if supported by substantial evidence, shall be conclusive.”). We shall affirm the SSA’s finding if it is supported by substantial evidence. Although a mere scintilla of proof will not suffice to uphold the SSA’s findings, the standard of substantial evidence requires no more than “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” We cannot substitute our own judgment for that of the SSA by reevaluating the facts, or reweighing the evidence to decide whether a claimant is in fact disabled. Thus, the issue before this court is not whether [Hughes] is disabled, but rather, whether the ALJ’s findings were supported by substantial evidence.
“Substantial evidence may be something less than the greater weight or preponderance of the evidence” (Young v. Secretary of HHS, 957 F.2d 386, 389 (7th Cir.1992)), and a finding may be supported by substantial evidence even if a reviewing court might have reached a different conclusion (Delgado v. Bowen, 782 F.2d 79, 83 (7th Cir.1986) (per curiam)).
Hughes contends that reversal or remand is in order because the ALJ’s decision is not supported by substantial evidence. More specifically, he charges that the ALJ:
1. failed to comply with SSR 83-20 when he ignored the medical evidence submitted after the Hearing and
2. inappropriately disregarded Dr. Kerr’s conclusion that Hughes suffered from mental impairments that would prevent him from engaging in gainful employment.
Those contentions will be addressed in turn.
Supplemental Medical Evidence
Hughes first claims that the ALJ failed to comply "with the SSR 83-20 directive that medical evidence should constitute the “primary element” of onset determinations (1983 Social Security Rulings 109, 110 (Dep’t Health & Human Services)). ALJ Sprague therefore erred, Hughes argues, in ignoring a significant body of medical evidence submitted after the Hearing (R. 217-40)15 — evidence that established that Hughes had indeed been treated for his physical impairments during a time period that the ALJ had deemed crucial in determining the point at which Hughes became unable to function as an assembler (see R. 17, 19).16
*994On February 14,1994 (over 3 months after the Hearing) Hughes’ counsel sent ALJ Sprague a 3-page cover letter and 23 pages of supplemental medical records extending from December 22, 1990 to December 18, 1993 (R. 214-40).17 ALJ Sprague had specifically informed counsel that additional medical evidence “would be appreciated” (R. 88) and, if forthcoming, would necessarily be considered in reaching a decision.18 Yet when he later issued his decision he never referred to those submissions (R. 14-22). Quite to the contrary, his opinion’s only comment as to evidence relating to the time period that was later covered by the additional evidence said that Hughes had orally “admitted during the hearing that he received little treatment between March, 1991 and August, 1992” (R. 19) (compare Bates v. Sullivan, No. 88 C 7134, 1989 WL 68517, at *4, 1989 U.S.Dist. LEXIS 7725, at *11 (N.D.Ill. June 15)). And there is no doubt that the ALJ had some critical facts dead wrong in consequence of that — his opinion contained this critical error, mixing a flat-out error with a partial truth to lead to a problematic conclusion (R. 17):
He did not have any medical treatment from March, 1991 to August, 1992.19
Hughes claims error on that score, asserting that “the ALJ completely ignored the post-hearing evidence” (P.Mem. 9). And Commissioner concedes that the ALJ never reviewed those documents (D.Mem. 4 n. 7). Indeed, the Appeals Council refers to the supplemental evidence as “new” without further explanation (R. 6).20
Nothing in the record explains why the ALJ did not review evidence that he had previously (and accurately) suggested could be material and whose “absence” he specifically highlighted in the course of reaching his decision.21 But the reason is really irrelevant. This is not at all the kind of situation as to which “the ALJ was not required to discuss every piece of evidence, and the weight to be given to this evidence remained within the discretion of the ALJ” (Diaz, 55 F.3d at 308). Instead what is critical is that ALJ Sprague was playing with less than what he himself had characterized as needed to make up a full deck.22
*995It is brae that the Appeals Council said that it had considered the additional medical evidence and found that “it does not warrant a change in the Administrative Law Judge’s decision,” which it said “is supported by the weight of the evidence” (R. 7). But that impermissibly erases the distinction between the factfinder (in this instance the ALJ) and a reviewing tribunal. Every litigant is entitled to have the factfinder weigh the evidence in the first instance, after which the reviewing court or agency properly applies a level of review that is more solicitous of the original decision than de novo review. It is no different than if this Court were to conduct a bench trial and decide the case while wholly ignoring a material part of the evidence before it — in that event the Court of Appeals plainly would (and should) remand the ease so that the parties would receive the type of fair trial (meaning in that instance one based on all the evidence) that had not been accorded them.
To be sure, a key aspect of what has just been said has been its reference to “ignoring a material part of the evidence.” If it is plain that the overlooked evidence could not have altered the result, the factfinder’s error in failing to consider it would of course be harmless, and a remand would be pointless. But in that respect the reviewing body— whether the Appeals Council or this Court— must respect the characterization that the ALJ himself had placed upon the type of evidence involved. Again it should be remembered that because the Appeals Council denied review, it is the ALJ’s decision that has become Commissioner’s final decision and is now under review (Diaz, 55 F.3d at 305 n. 1). So this opinion turns to the question of materiality. And in that respect this Court must determine as a matter of first impression whether there is a “reasonable possibility” that the additional evidence submitted by Hughes would have changed the outcome of the Hearing (Nelson v. Bowen, 855 F.2d 503, 506 (7th Cir.1988)).
Here is what ALJ Sprague said in pertinent part when determining the onset date of Hughes’ disability (R. 19):'
After a careful consideration of all the evidence in this case, I find that the claimant has failed to sustain his burden of proof. This is especially so in relation to his light job as assembler of light airplane parts. Usually, he lifted items weighing less than 10 pounds. He only occasionally had to lift items weighing up to 30 pounds. It seems that his impairments did not get severe enough to be unable to perform this work until about October, 1992. This is when the claimant’s arthritis, and pain, got very severe.
The claimant admitted at the hearing that he received little medical treatment between March, 1991 and August, 1992. He said his condition didn’t get real bad until about one year ago. He could get around better before that.
Dr. Trafimow performed a consultative orthopedic examination on the claimant on July 23,1992. In conclusion, he stated: “I am unable to find any objective evidence of the reasons for the claimant’s pain.” (Exhibit 25, p. 4).
Thus the ALJ cited three factors in support of his decision: (1) Hughes’ statement that his condition had worsened about one year before the Hearing, (2) the absence of medical treatment from March 1991 to August 1992 and (3) the July 23, 1992 examination performed by Dr. Trafimow.
This Court’s de novo review of the materiality issue (Nelson, 855 F.2d at 506) leads it to an entirely different conclusion from that reached by the Appeals Council.23 As to *996Hughes’ condition of health from March 1991 to August 1992 (which was a stated cornerstone of the ALJ’s decision to reject Hughes’ asserted onset date), it is clear that the additional evidence might well have rebutted the ALJ’s impression that Hughes must have been “doing pretty good during that period” (R. 64) because there was no apparent need for medical treatment. Though the actual evaluation of the added evidence will be for the ALJ to make, a brief recital is in order to demonstrate its materiality in the “reasonable possibility” sense.
Although the copies of the supplemental records provided to this Court by the United States Attorney as part of the administrative record pose some real problems in reading the doctor’s handwriting,24 they plainly report “persistent pain” and “severe spasms” suffered by Hughes dating back to January 29 and March 6,1991 (R. 219) and continuing thereafter (see R. 220-22). Relatedly the August 1991 CT scan revealed mild bulging between some discs in Hughes’ spine, mild soft tissue and bony stenosis (R. 234). That CT scan also prompted the examiner to note that further evaluation might be necessary if there was “clinical suspicion for a herniated disc” (id.). In November 1991 Hughes again complained of lower back pain with sciatica—a condition usually associated with a herniated lumbar disc (Stedman’s Medical Dictionary 1262 (5th unabridged lawyer’s ed. 1982)). Those observations are entirely consistent with Dr. Sawlani’s earlier view on December 12, 1990 that a narrowing of the disc space between L5-S1 could not be ruled out (R. 125) — “[gjreater than 90% of herniated discs of the lumbosacral spine occur at L4-5 or L5-S1” (6 Lawyers’ Medical Cyclopedia § 44A.37, at 738)—and with Dr. Kaplan’s March 6, 1991 finding of a positive straight-leg raising at 30°25 (R. 128) (id.).
Neither this Court nor the Appeals Council may properly engage in its own initial evaluation as to the weight to be given the additional records — that is for the ALJ to do. Surely those records are both relevant and material to a decision regarding Hughes’ condition during the critical time period cited by the ALJ himself. SSR 83-20 provides that a claimant’s asserted onset date controls if supported by such records, and SSR 88-13 directs the ALJ to investigate records of pain medication and treatment when evaluating the evidence of the claimant’s pain (see R. 18). It will be recalled that the only other evidence cited by the ALJ when fixing the onset date was one ambiguous statement by Hughes himself26 and one conflicting medical report (see Appendix). It is an understatement to say that there is a “reasonable possibility” that the additional evidence would have tipped the balance in Hughes’ favor.
In sum, this Court finds that the additional records are plainly material to the issue of Hughes’ onset date, and as said in Nelson, 855 F.2d at 507-08 (adapted to this case):
Given the paucity of the evidence before the ALJ relevant to this issue and the lack of evidence clearly contradicting the additional evidence offered by [Hughes] before the Appeals Council, that evidence, if considered by the ALJ, might reasonably have affected his determination....
That requires a remand to Commissioner for consideration of the additional evidence (and because the situation does not qualify as a *997“sentence six” remand under Section 405(g), it is perforce a “sentence four” remand (Shalala v. Schaefer, — U.S. -, -, 113 S.Ct. 2625, 2629, 125 L.Ed.2d 239 (1993); Melkonyan v. Sullivan, 501 U.S. 89, 99, 111 S.Ct. 2157, 2163, 115 L.Ed.2d 78 (1991)).
Hughes’ Claimed Mental Impairment
Hughes also claims (P.Mem. 14):
While Plaintiffs personality disorder may not be manifested at listings level severity, the ALJ nevertheless erred in accepting Dr. Blackman’s unsupported assertions as evidence that Plaintiff had no mental limitations on his ability to engage in substantial gainful employment.
Citing Garrison v. Heckler, 765 F.2d 710, 713 (7th Cir.1985) for the proposition that a consulting expert cannot supply substantial evidence simply by contradicting another expert’s findings (P Mem. 13), Hughes predictably argues that Dr. Kerr’s report should have trumped Dr. Blackman’s testimony. But that argument is both tardy and unpersuasive here.
As an initial matter, Hughes really waived the argument that the ALJ erred in assessing Hughes’ mental impairment. Hughes’ petition to the Appeals Council makes no mention of his claimed mental impairments, much less any claim that the ALJ improperly credited Dr. Blackman’s testimony over that of Dr. Kerr (R. 211-12). Papendick v. Sullivan, 969 F.2d 298, 302 (7th Cir.1992) reconfirms the principle that issues sought to be raised on appeal to a federal court must first have been raised administratively. This Court could therefore properly “decline to consider issues not considered by the Appeals Council” (id). But because the United States Attorney has addressed the merits of Hughes’ mental impairment argument without asserting waiver, the waiver issue may itself be waived (cf. Barrera v. Young, 794 F.2d 1264, 1269 (7th Cir.1986)), so this Court will likewise consider Hughes’ claim.
Commissioner has promulgated a Listing of Mental Impairments that, if properly shown by a claimant, presumptively establish that the claimant is disabled and is thus entitled to receive benefits (Reg.Pt. 404, Subpt. P, App. 1, §§ 12.00-12.09; Young, 957 F.2d at 389). For a claimant to qualify, the Regulations generally require: (1) documentation of any medically determinable mental impairments (the “A” criteria) that if satisfied leads to (2) an assessment of functional limitations that those impairments impose on the claimant’s activities (the “B” criteria).
At the Hearing, Hughes submitted as evidence of his mental impairment Dr. Kerr’s psychological evaluation suggesting that Hughes met the requirements of two listings: 12.08 (Personality Disorder) and 12.09 (Substance Addiction Disorder) (R. 164). But during the Hearing the ALJ observed that while “Kerr says [Hughes] meets 12.08[ ] he didn’t check enough boxes on that” (R. 87)— that is, Dr. Kerr had failed to indicate three functional limitations of the severity required by paragraph B in listing 12.08 (see R. 19, 170; Reg.Pt. 404, Subpt. P, App. 1, § 12.08). Hughes’ counsel conceded the point, stating (R. 88):
Right. Right, as I said, I didn’t present this as a case where he meets the listing.
Then the ALJ went on to conclude that Hughes also failed to meet the requirements of listing 12.09 because the “claimant’s substance abuse is in good remission, and no longer causes any limitations” (R. 19).
But Hughes correctly asserts that his failure to meet the listing requirements under sections 12.08 and 12.09 does not end the inquiry, for his mental impairment might still have been so severe as to hinder his gainful employment. As Hargis v. Sullivan, 945 F.2d 1482, 1491 (10th Cir.1991) teaches:
Pursuant to Congress’ mandate, the Secretary must consider the combined effects of impairments that may not be severe individually, but which in combination may constitute a severe medical disability. 42 U.S.C. § 423(d)(2)(C) (1988). The Secretary’s regulations indicate that “[t]he determination of mental RFC is crucial to the evaluation of an individual’s capacity to engage in substantial gainful work activity when the criteria of the listings for mental disorders are not met or equaled but the impairment is nevertheless severe.” 20 C.F.R. Part 404, Subpt. P, App. 1, § 12.00(A). The Secretary, pursuant to *998his own regulations, cannot therefore dismiss a claimant’s mental impairment once there is a finding that the claimant does not meet the listings. A claimant’s mental impairment must also be evaluated in combination with the effects of other impairments.
ALJ Sprague did precisely that (R. 19). After finding the listings inapplicable, the ALJ did go on to consider whether Hughes suffered from a mental impairment that might impede his ability to work. ALJ Sprague found no such impairment — only an inability to process “complex tasks from a mental point of view.” It was unnecessary for the ALJ to consider how Hughes’ mental shortcomings might interact with other impairments — Hargis and Reg. Part 404, Subpt. P, App. 1, § 12.00(A) require that course to be pursued only when an impairment is “severe.”27
That leaves as final question whether the test results cited and interpreted by Dr. Blackman, and referred to by the ALJ (R. 19), amount to substantial evidence of Hughes’ ability to work. Hughes cites Garrison, 765 F.2d at 713 in support of his contention that the ALJ was wrong to reject Dr. Kerr’s “careful, thoughtful analysis” (P.Mem. 13), arguing that those conclusions were based upon an in-depth interview and testing while Dr. Blackman’s conclusions amounted to “unsupported assertions” (id. 14).
Hughes’ problem is that Garrison does indeed control, but that it requires affir-mance of the ALJ’s decision as to Hughes’ claimed mental impairment. Here is what Garrison, 765 F.2d at 713 says:
Allen [v. Weinberger, 552 F.2d 781 (7th Cir.1977) ] and Whitney [v. Schweiker, 695 F.2d 784 (7th Cir.1982)] stand in some tension with [.Richardson v.] Perales [, 402 U.S. 389, 91 S.Ct. 1420, 28 L.Ed.2d 842 (1971) ]. We hesitate to extend them. At all events, neither ease holds that consulting physicians’ reports are not “substantial evidence” when the consulting physician brings to the case something of value to the administrative decision, such as greater expertise with an ailment, greater impartiality, or a greater range of experience that facilitates a comparison of one case against a standard or rule of decision.
And id. at 715:
The preference for the views of the treating physician discussed in Allen and Whitney applies only when ability to observe the claimant over an extended period is essential to an accurate understanding.
Unlike the situation as to Hughes’ back problems (see Appendix), Hughes is scarcely in a position to urge that the “ability to observe the claimant over an extended period [was] essential to an accurate understanding” of his mental condition. After all, Hughes contends that Dr. Kerr’s findings should control, yet the record contains evidence of only a single visit to Dr. Kerr on June 19, 1992 (R. 155, 164). Furthermore, while Hughes complains that Dr. Blackman’s reasoning was cryptic or even non-existent (P.Mem. 14), that misconceives Dr. Blackman’s role. Dr. Blackman was retained only to interpret Dr. Kerr’s data — it was therefore to be expected that he would provide “conclusions rather than reasons” (Garrison, 765 F.2d at 712). In fact, Hughes’ argument accepts as its premise that this is a case much like Garrison to the extent that Hughes’ mental condition “is subject to reasonably precise measurements” (id. at 714): Dr. Kerr assessed Hughes’ condition by way of the Wechsler Memory Scale (in part), Psychiatric Report Form DF-104, Bender Gestalt Test, Wech-sler Adult Intelligence Scale-Revised, Wide Range Achievement Test for reading and the Cornell Psychiatric Index (R. 156-58; P.Mem. 13 n. 11). Those tests are precisely the kind of data reviewed by consulting experts. And as Garrison, 765 F.2d at 714 teaches:
*999Unless the claimant establishes that the specialists misread or misunderstood the results of the test, or that the objective tests do not accurately describe the impairment, the consulting physicians’ reports may supply substantial evidence for the agency’s finding.
Thus confronted with the raw data gathered by Dr. Kerr and the opposing interpretations of that data by Dr. Kerr and Dr. Blackman, the ALJ simply agreed with the latter (R. 19), thus fulfilling his duty to resolve conflicting medical evidence (see Diaz, 55 F.3d at 306 n. 2). In fight of the recited reliance by both Dr. Blackman and the ALJ on the very tests that Hughes champions (R. 81 and 19-20), the ALJ’s finding as to Hughes’ mental competence was supported by substantial evidence. That issue calls neither for reversal nor for reconsideration on the required remand.
Conclusion
Hughes contends and Commissioner concedes that the ALJ never reviewed the additional medical evidence that was submitted after the Hearing. This Court finds that evidence was plainly material, for what ALJ Sprague incorrectly labeled as its absence was a key element of the ALJ’s decision to deny Hughes disability benefits. However, Hughes’ further contention that the ALJ erred in discrediting the testimony of Dr. Kerr is without merit. Accordingly, each litigant’s motion for summary judgment is denied, and this action is remanded to Commissioner for further action consistent with this opinion (including the Appendix). Commissioner’s decision is reversed.28
APPENDIX
Although Hughes has pointed only to the additional evidence submitted after the Hearing and to the evidence of his mental impairment, another shortcoming of the ALJ’s decision merits attention on remand. ALJ Sprague’s opinion failed to comment at all on any of the evidence in the record tending to support Hughes’ asserted onset date. This Court (Oyen v. Shalala, 865 F.Supp. 497, 507 (N.D .Ill.1994)) has echoed the teaching of our Court of Appeals that it is the duty of every ALJ “to explain the basis of his or decision with particularity.” Herron, 19 F.3d at 333 (citations omitted) reconfirms that duty:
Our cases consistently recognize that meaningful appellate review requires the ALJ to articulate reasons for accepting or rejecting entire fines of evidence. Although a written evaluation of each piece of evidence or testimony is not required, neither may the ALJ select and discuss only that evidence that favors his ultimate conclusion. We have repeatedly stated that the ALJ’s decision must be based upon consideration of all the relevant evidence, and that the ALJ “must articulate at some minimal level his analysis of the evidence.”
It is therefore a matter of concern that the ALJ chose not to comment on such items as (1) the December 12,1990 x-ray that demonstrated “degenerative changes” in Hughes’ spine “with osteophyte formation” and a “marked narrowing” of disc spaces (R. 125), (2) Dr. Kaplan’s admonition that Hughes not return to work due to “arthritis in the lumbo-sacral spine, feet, etc.” (R. 124) and (3) Dr. Kaplan’s March 6, 1991, finding that Hughes suffered from osteo-arthritis, degenerative changes and muscle spasms in his paraspinal muscles (R. 126). Even more troublesome is the ALJ’s total silence as to Dr. Steward’s May 2, 1992 examination of Hughes — an examination in which Hughes was found incapable of working an 8-hour day (R. 150), as is required even for sedentary work (see Sample v. Shalala, 999 F.2d 1138, 1142 n. 6 (7th Cir.1993)).
In that latter respect, even though the ALJ’s reliance on Dr. Trafimow’s July 23, 1992 findings may perhaps be viewed as an implicit rejection of the findings of Dr. Steward, any such practice raises “considerable difficulties for a reviewing court” (Judge Heaney, 7 Hamline L.Rev. at 15). In that regard the ALJ not only failed to give “good reasons” for discounting or rejecting the *1000opinion of a “treating source” as required by Reg. § 404.1527(d)(2), but he also favored the opinion of a physician who had examined Hughes only once, even though “[sjerial observation [such as that conducted by Dr. Steward] is very important in management of patients with back pain” (Principles of Ambulatory Medicine 875). Furthermore, both (1) the ALJ’s reliance on Dr. Trafimow’s failure to find “any objective evidence” of pain (R. 19) and (2) the ALJ’s emphasis on the “fact” that it was only since October 1, 1992 that “many of the claimant’s complaints have been supported by the medical evidence” (R. 20)1 appear to be at odds with the revised version of Reg. § 404.1529(c)(2) (see Knight, 55 F.Bd at 313-14 and cases cited there).
Because it has proved necessary to remand this case in any event, there is no need to decide whether those deficiencies in the ALJ’s original decision would themselves have rendered it vulnerable under the “substantial evidence” standard. Instead the ALJ can cure those problems on remand.