Many Social Security disability appeals end with a “partially favorable decision” that accepts some, not all, of a disability claim, and often adjusts the onset date. You can appeal a partially favorable decision if you sincerely believe that the judge has made an error in fact or in application of the law. The procedure would be to file a Request for Review to the Appeals Council. However, remember that you’re taking a risk. An appeal of this decision means the entire claim is again in play, including the finding of disabled that you were seeking and won from Social Security. The Appeals Council may decide you’re not disabled at all, or they may just agree with the judge’s onset date, or they may move the onset date further up, or they just might find that you had a “closed period” of disability, meaning you are only entitled to benefits for a limited time in the past. If the Appeals Council remands the decision, it will go back to the same judge for reconsideration, and this kind of thing is usually understood by Social Security as a finding that your partially favorable notice was too favorable. You would have to make a pretty convincing case for a judge to agree with you and admit he or she has made a mistake.