The Global Assessment of Function (GAF) is a way of describing a person's symptoms and mental abilities along a scale of 1 to 100. The better the score, the better the function. This rating system applies only to mental disorders, and the doctor completing the form is supposed to not consider any limitations caused by physical problems.
The American Psychiatric Association (APA) periodically issues guidelines classifying mental disorders and what criteria should be used for diagnosis, called the Diagnostic and Statistical Manual. The Social Security Administration (SSA) used the third version of the Diagnostic and Statistical Manual (DSM-3) as a loose framework for many of its current mental disorder listings (medical regulations specifying the criteria needing to be present for disability to be found). DSM-4 introduced the GAF scoring system. But then DSM-5 dropped the GAF system completely, because it was of little benefit to clinicians and questionably reliable.
The SSA has never had an official policy to grant disability benefits based on a GAF score. Some people who have had experience with the VA disability system may assume that the SSA works the same way (see below). On the Internet, there are even Social Security disability-related websites that state that the SSA commonly uses GAF scores to determine mental status, but this is not correct. If a particular SSA adjudicator has used GAF scores as the sole basis for a decision, that would have violated SSA's own regulations.
The structure of most of the SSA's mental disorder listings contains certain criteria that are generally accepted by the medical profession to be used to make a diagnosis. These clinical severity findings could be hallucinations, delusions, fears, memory problems, or many other abnormalities, depending on the type of mental disorder.
After confirming the diagnosis, the overall severity of the diagnosed disorder is then decided using of all the other information in the file, specifically the person's ability or inability to function in ways that would affect their ability to work. The important types of function involve:
If the SSA receives a GAF score as a part of the medical evidence, it is simply one element of the disability assessment, and carries relatively little weight in comparison to more objective and detailed information about a person's mental disorder. The entire GAF scoring system can be put on a single page (the GAF scoring sheet can easily be found through an Internet search). Basically, the scoring criteria are very general in nature and there is no information on how the scoring information was reached. GAF scores fail to have the quality of standardized psychological testing required by the SSA—probably because it is just an opinion of a psychiatrist rather than a valid test result like an IQ score.
The SSA is required to decide if a disability applicant has a "medically determinable impairment," meaning a disorder based on objective evidence that an adjudicator can use to make an independent decision. In an alleged heart attack, for example, the SSA would need objective tests, such as heart tracings, an imaging study, or enzymes from damaged heart muscle, to reach that diagnosis. In contrast, the GAF score is someone's conclusion about how much a mental disorder limits a person's function. That proves nothing objectively. More evidence is needed to give the full picture.
However, a GAF score doesn't mean nothing to the SSA. Like other opinion-evidence, it is a pointer to a possible problem, just as an alleged a heart attack is a pointer to the need of obtaining objective evidence.
If the evidence shows that a low GAF score (which shows a poor ability to function mentally) is in conflict with other evidence showing a much better ability to function, then that conflict should be resolved by further investigation, since the GAF score is by its nature subjective. Social Security can gather more evidence to either support or a GAF score by either:
When an SSA claims examiner, medical consultant, or administrative law judge writes a rationale for an applicant's approval or denial, the decision should be explained in regard to the reasoning used.
If a high GAF score is in the applicant's file (meaning the applicant has a good ability to function mentally), but it doesn't fit with all the other evidence in a case, this also suggests a conflict that should be resolved. Resolving the conflict could sometimes be as simple as the DDS claims examiner or medical consultant explaining why the other data in the file means the high GAF score is invalid.
On the other hand, in a written rationale for denial, an applicant's file might mention a high GAF score as one factor supporting that conclusion. In a written rationale for an allowance (an approval of disability benefits), a low GAF score might similarly be cited as a part of consistent data supporting such a decision.
Whether high or low, a GAF score is a weak piece of evidence medically, because it is merely one person's opinion, and the SSA doesn't decide cases on opinion. Hence GAF scores can be used only in the context of all the other evidence.