dissenting:
On appeal, Malak contends that the Commissioner’s decision was not supported by substantial evidence. I would find that the ALJ’s residual functional capacity (“RFC”) determination was not based on substantial evidence where the ALJ relied almost exclusively on Dr. Mills’ testimony, which was contradictory. I, therefore, respectfully dissent.
At the 2000 and 2003 hearings, Dr. Mills was asked to give his opinion as to Malak’s medical condition in 1988, taking into account all the subsequent medical evidence on record. In 2000, Dr. Mills testified that from 1988 through early 1995, Malak had the RFC to lift and carry up to 25 pounds occasionally and 10-15 pounds frequently, to stand and walk for four hours out of an eight-hour day, to sit for six hours out of an eight-hour day, and to occasionally stoop or kneel. (A.R. 686, 699-701, S.E.R. 33, 46^8.)
At the January 2003 hearing, however, Dr. Mills testified that Malak “almost certainly” equaled listing 4.04C from June 17, 1988 through his bypass surgery in June 1995. The ALJ rejected this opinion, stating that it improperly credited Malak’s testimony of his symptoms. However, the ALJ’s assertion that Dr. Mills was crediting Malak’s testimony in the latter opinion grossly mischaracterizes the record. The ALJ asked whether Malak would have equaled a listing in December 1988, “using 20/20 hindsight” and taking “all of the medical evidence” into consideration. (A.R. 1325, S.E.R. 325.) Dr. Mills, when rendering his opinion, clarified that his opinion was based on the records and not on Malak’s alleged symptoms.1 Of course, whether a claimant equals a listing is a question for the Commissioner, so the ALJ was not required to accept Dr. Mills’ testimony on this point. See Soc. Sec. Ruling 96-5p, 1996 WL 374183 (1996). Nonetheless, Dr. Mills’ testimony that Malak equaled a listing in 1988 is plainly inconsistent with his previous testimony that Malak had the RFC for light work.
The medical opinions on record, therefore, consisted of Dr. Mills’ internally inconsistent testimony, the opinions of treating physicians, and the opinions of non-*488treating physicians. I agree with the majority’s conclusion that the ALJ need not have accepted the opinions of the treating physicians because these opinions were brief, conclusory, and inadequately supported by clinical findings. See Thomas v. Barnhart, 278 F.3d 947, 957 (9th Cir.2002).
However, the opinion of Dr. Aintablian (A.R. 1068-71, S.E.R. 160A-C), a non-examining physician, consists of a detailed analysis of the medical evidence of record. He concludes that, in 1988, Malak had a Class III heart according to the New York Heart Association Function Classification. This classification indicates marked limitations in activities, even during less-than-ordinary activities. Because Dr. Aintablian is a non-examining physician, his opinion was not entitled to any greater inherent weight than that of Dr. Mills. However, Dr. Mills’ opinion at the 2000 hearing, on which the ALJ relies, was contradicted by his own testimony at the 2003 hearing. It is the ALJ’s responsibility to resolve conflicts in the evidence, but a gross mischaracterization of the record is not a permissible means of doing so. The ALJ’s resulting RFC determination, therefore, is not based on substantial evidence on the record as a whole. I, therefore, would remand the case for a proper RFC determination.
I would also remand because the ALJ committed legal error in failing to properly determine the onset of Malak’s disability. Here, it is undisputed that Malak was disabled in 1995. The key question, therefore, is whether the onset date of Malak’s disability pre-dates the expiration of his insured status on December 31, 1988. Soc. Sec. Ruling 83-20, 1983 WL 31249 (1983),2 notes that the onset date is critical in Title II cases because it may be, as it is in this case, “determinative of whether the [claimant] is entitled to or eligible for any benefits.” Id. at * 1. Where evidence of the onset date is ambiguous, the ALJ must consult with a medical adviser. Armstrong v. Comm’r of Soc. Sec. Admin., 160 F.3d 587, 590 (9th Cir.1998); Soc. Sec. Ruling 83-20. The ALJ has a duty to fully and fairly develop the record where evidence is ambiguous. Tonapetyan v. Haler, 242 F.3d 1144, 1150 (9th Cir.2001).
It is established that medical evidence post-dating the date a claimant was last insured (“date of last insured”) may be relevant in determining whether a disability had an onset prior to the expiration of the claimant’s insured status. See Floten v. Sec’y of Health & Human Servs., 44 F.3d 1453, 1461 n. 5 (9th Cir.1995); Smith v. Bowen, 849 F.2d 1222, 1225 (9th Cir.1988). See also Newell v. Comm’r of Soc. Sec., 347 F.3d 541, 547 (3d Cir.2003); Ivy v. Sullivan, 898 F.2d 1045, 1049 (5th Cir.1990); Basinger v. Heckler, 725 F.2d 1166, 1169 (8th Cir.1984); Soc. Sec. Ruling 83-20. As the majority notes, much of Malak’s claim depended on extrapolating his probable condition in 1988 from medical evidence post-dating the date of last insured (such evidence is hereinafter referred to as “subsequent medical evidence”). Subsequent medical evidence is particularly useful in a case, like the one at bar, where it is clear that the claimant became disabled at some point in time, but *489the contemporaneous medical evidence is insufficient to establish whether the onset of disability pre-dates the date of last insured. See e.g., Ivy, 898 F.2d at 1048-49 (holding that ALJ erred in determining the claimant’s onset date based only on contemporaneous medical evidence where the subsequent medical evidence established an earlier onset date). As the Social Security Administration explains, “With slowly progressive impairments, it is sometimes impossible to obtain medical evidence establishing the precise date an impairment became disabling.... In such cases, it will be necessary to infer the onset date from the medical and other evidence that describe the history and symptomatology of the disease process.” Soc. Sec. Ruling 83-20, 1983 WL 31249 at *2
During the November 8, 2000 and January 22, 2003 hearings, the ALJ largely restricted the medical expert to basing his opinion on the contemporary medical evidence; there were only two brief occasions where Dr. Mills was permitted to consider all the relevant medical evidence on record including the subsequent medical evidence. These portions of Dr. Mills’ testimony are the most relevant to determining the onset date of Malak’s testimony. As was previously discussed, Dr. Mills gave contradictory testimony regarding Malak’s onset date on these occasions. When, at the 2003 hearing, Dr. Mills contradicted his previous testimony and indicated a June 1988 date of onset, the ALJ was obligated to continue consulting with Dr. Mills regarding the date of onset by asking him to elaborate and by asking him to explain the apparent inconsistencies in his testimony. See Tonapetyan, 242 F.3d at 1150 (ALJ obligated to fully and fairly develop the record where evidence is ambiguous); Armstrong, 160 F.3d at 590 (ALJ obligated to consult with medical expert regarding date of onset of disability). The ALJ did not ask him to elaborate and give an opinion as to Malak’s RFC in 1988; rather, he repeatedly interrupted Dr. Mills in an apparent attempt to mold his testimony (A.R. 1326-28, S.E.R. 326-28). And, instead of asking Dr. Mills to explain the apparent inconsistencies, the ALJ rejected Dr. Mills’ 2003 testimony based on a gross misrepresentation of the record.
Given the ALJ’s obligations to fully and fairly develop the record when evidence is ambiguous, Tonapetyan, 242 F.3d at 1150, and to consult with the medical adviser regarding the onset date of the disability, Armstrong, 160 F.3d at 590, I would find that the ALJ committed legal error when he largely prevented Dr. Mills from rendering an opinion as to the onset date based on all the relevant medical evidence and did not attempt to resolve the conflicts in Dr. Mills’ testimony by developing the record further.
On appeal, Malak did not explicitly raise this issue; rather, he argued that, in light of both the subsequent and contemporaneous medical evidence, the ALJ’s opinion was not based on substantial evidence on the record as a whole. Despite Appellant’s failure to raise this issue, I would nonetheless address it because it falls within a well-established exception to the waiver doctrine: the issue is purely legal and the pertinent record has been fully developed. See Harden v. Roadway Package Systems, Inc., 249 F.3d 1137, 1141 (9th Cir.2001). Deciding this issue would not be unfair to Appellee where Appellant’s arguments referenced the key elements of this issue, namely the use of subsequent medical evidence and the contradictions in Dr. Mills’ testimony.
Therefore, because the ALJ’s determination of Malak’s RFC in 1988 was not based on substantial evidence on the record as a whole and because the ALJ erred *490in failing to properly determine the onset date of Malak’s disability, I would reverse and remand to the district court with orders to remand the matter to the Commissioner.
. When Dr. Mills began to answer, the ALJ interrupted to clarify that he was not to base his opinion on Ohanian’s hypothetical questions that had made certain representations as to Malak’s symptoms in 1988. Dr. Mills made it clear that his opinion was only based on the records, not on Malak's alleged symptoms:
[ALJ:] Well, now, wait a minute. I want you to answer this question, just not based on his testimony—
[Dr. Mills:] No. I’m not doing it on that. I’m doing it on the evidence.
Q —just on the—
A Records.
Q —on the records.
(A.R. 1326, S.E.R. 326.) The records before Dr. Mills only consisted of the medical records. He had no transcript of Malak’s testimony from the 2000 hearing. Therefore, his insistence that he was only relying "on the records” clearly indicates that he was excluding Ohanian's representations as to Malak’s symptoms.
. Social Security Rulings are issued by the Commissioner to clarify the social security regulations and the agency's policies. Holohan v. Massanari, 246 F.3d 1195, 1202 n. 1 (9th Cir.2001). While they are binding on all components of the Social Security Administration, 20 C.F.R. § 402.35(b)(1), they do not have the force of law. Holohan, 246 F.3d at 1202 n. 1. Nonetheless, “because they represent the Commissioner’s interpretation of the agency's regulations,” they are given some deference insofar as they are not inconsistent with the statute or regulations. Id. (citing Bunnell v. Sullivan, 947 F.2d 341, 346 n. 3 (9th Cir.1991) (en banc)).