The situation is complicated enough but the language Social Security can use to describe the process can throw one off all by itself but "The Five Step Sequential Evaluation" is the name that's given. Social Security Disability's description is found here http://www.socialsecurity.gov/OP_Home/rulings/di/01/SSR86-08-di-01.html
At every hearing, the Social Security disability judge will go through these five steps in some form or fashion. This is the core of the case your social Security disability lawyer prepares; it is how the judge looks at the case; it is how the decision is written; and it is how the Appeals Council in Virginia or a federal judge looks at an appeal from the local Social Security judge in Tuscaloosa and Birmingham. This is where the vast majority of cases are decided as wins and losses.
If you want to do this without a lawyer, this is what you must prove and these are the five steps:
1) Is the individual engaging in substantial gainful activity (SGA)?
Roughly translated as "Are you working full time or working part time and earning more than $1,000 a month?" If you're working, the case ends here. Nothing more is done. The case is over. If no substantial gainful activity, the Social Security Disability case moves on to the next issue.
2) Does the individual have a severe impairment?
That is, do you have a mental and or physical problem that could significantly interfere with work? If the answer is no, the case stops here. If yes, the case goes on to the next issue.
3) Does the individual have an impairment that meets a Listing?
This is the same issue we talked about in the section on Listings for a pay on the record. If the medical records show that your conditions are so bad they meet the extreme standards of a Listing, the case stops here with an award. If not, then the Social Security disability case goes to the next step. As a practical matter, very few cases stop here during the Social Security hearing. A Listing may be found by the judge when he writes the order a few weeks or months later but it makes sense to go through the whole disability process while everyone is there in the courtroom because a more thorough hearing that covers all issues is often better. More testimony can often provide more support for the listing .So, the Social Security disability hearing generally goes on to step four.
4) Can the person return to past relevant work?
If you can go back to any of your old jobs and do those 8 hours a day for 40 hours a week, the case ends here with a finding of "not disabled." This is based on medical evidence. If you can't go back to your old job or jobs, then the case moves on to the next step. Most appealed cases are decided with the evidence in step five. Cases can be won here if folks are 50-54, approaching advanced age, or 55+, advanced age. If older individuals cannot go back to past work and they meet the special criteria for these ages then the case can stop by "gridding out. (There really is a sheet of paper laid out in a grid that we use at these ages for particular limits.)
5) Can the individual make adjustment to other jobs available in the national economy?
It is the government’s that is Social Security Disability's, burden to prove this. The best working assumption for a hearing - and the only safe one - is to assume they can prove this and be prepared to show this is wrong with medical and legal arguments. If you can pass through this gauntlet to show there are no other jobs available, then you have won. If not, then you go on to try to win in two forums where you have less chance to win.