Why does it take so long to get a decision on a Social Security Disability or SSI Disability case?

A claim that is filed with the social security administration on the basis of disability can take quite a while to process at the first stage. The first stage, of course, is the application stage. How long does this stage take? There are no deadlines and cases can take weeks or months. Most often, a decision on an application will be handed down in three or four months. But...sometimes it can