The Social Security Adminstration ("SSA") uses a five step evaluation process to determine whether a claimant is eligible for disability benefits. 20 C.F.R. §§ 404.1520; 416.920. There is also a durational requirement: the impairment must have lasted or be expected to last at a disabling level for at least 12 months. 20 C.F.R. §§404.1509; 416.909.
The elements of the sequential evaluation are described briefly here. The full text of the regulations is available on Westlaw and Lexis, or at the Social Security Administration website.
Substantial gainful activity is work activity that involves doing signficiant physcial or mental activities for pay or profit. SSA presumes that work activity is substantial gainful activity if the earnings are more than $860/month (2006 value).
This is a de minimus standard. Impairments are considered "non-severe" only if such impairments cause no more than a slight abnormality having a minimal effect on a claimant's ability to perform basic (physical and/or mental) work activities.
Basic physical work activities include sitting, standing, walking, bending, stooping,lifting, carrying, reaching, handling,etc. Basic mental work activities include following instructions, being able to accept supervision, getting along with coworkers and supervisors, being able to maintain attention and concentration, being able to follow work rules and behave appropriately in the work place, etc.
The Social Security regulations set out listings of impairments in 20 CFR pt. 404.1599, Appendix 1. There are listings for 14 different categories of impairments. Each listing sets out findings, signs and symtpoms for specific impairments. If the claimant's condition meets the criteria for one or more of the listings, the claimant meets the medical criteria for disability.
This step requires two separate inquiries.
First, the claimant's residual functional capacity must be determined. The claimant's residual functional capacity (RFC) is an assessment of what the claimant can still do (physically and/or mentally) despite his or her impairments. RFC is determined by SSA on the basis of the medical evidence -- including the claimant's medical records, the reports of SSA's consultative physicians, and, if available, an assessment by the claimant's treating physician(s) -- and the claimant's testimony. Treating source opinions regarding the claimant's ability to perform work activity, if substantiated, are entitled to great or controlling weight in the disability determination and often make or break a claimant's case.
Second, the claimant's RFC must be compared to the functional requirements of the claimant's past relevant work. This is work performed within the 15 years prior to the date of application. It does not include work that occurred only for very brief periods or on a sporadic basis. The SSA evaluates the functional requirements of past work both on the basis of the way the claimant performed it and as it is generally performed.
For this step, SSA has adopted the Medical-Vocational Guidelines, set forth in the regulations at 20 CFR Pt. 404.1599, Appendix 2. These guidelines take into account the claimant's RFC, age, education and work experience. They are commonly called the "grids," because they consist of three tables laid out in a grid fashion. There is a grid for medium, light and sedentary work. Each table evaluates work capacity based on age, education level, and work experience. Each rule of the grid sets out a finding of disabled or not disabled for claimants who meet the exact requirements of the rule. To the extent the claimant's RFC and educational/vocational criteria does not match the criteria of a specific medical/vocational guidelines, the grids are nonetheless used as a "framework" for determining whether the individual is disabled at step five.