If you have been denied twice on a Social Security disability claim, you must file a Request for Hearing. You have 60 days to file this appeal after receiving a denial of your Request for Reconsideration. Social Security will review your file, order any relevant medical records and schedule a hearing, at which you will argue for your claim in front of an administrative law judge. There are several reasons judges deny claims, so it's best to prepare ahead of time and hire the services of a professional representative.
Your medical records must support your claim of disability. You must have an illness or injury that has lasted, or is expected to last, at least twelve months or to result in your death. The disability must prevent you from performing your past relevant work, and your treating doctors must document this fact in their notes. If you don't have sufficient medical evidence, Social Security will deny your claim, even if you appeal it to the hearing level.
The judge may find that despite your disability, you are still able to perform some kind of work in the current economy. Your skills may be transferable to a job that is not as physically demanding, or you may be able to retrain for another line of work. Social Security often points this out in the denial letters it sends out and may summon a vocational expert to testify in support of its contention. You should be prepared to argue against transferable skills, or retraining, at the hearing.
Social Security and you have the right to summon witnesses to the hearing. This can include friends, relatives, coworkers and job supervisors. If they appear, the judge can question them about your ability to work; and if those with relevant knowledge appear to support the agency's position that you can return to work or can retrain for another occupation, your claim will likely be denied. You or your representative should always examine the witness list provided by Social Security before the hearing and prepare to rebut any testimony against you.
At your hearing, the judge may show an interest in your daily activities: what you do all day, both inside and outside of the house, and how you interact with others. If you can function normally, take care of your personal needs and interact with others -- even informally -- the judge may find that you still have a capacity for work. Disability claims have been denied on the basis that claimants can still function mentally, even though they suffer physical disabilities. They have also been denied on the basis that the claimant was able to show up to the hearing and provide a lucid explanation of why she can't work.