This survey has usually proven to be the most accurate measure. Part of the survey includes questions concerning disability. It's not about claims; it's about answers to the following questions.

1. Are you deaf, or do you have serious difficulty hearing?

2. Are you blind, or do you have serious difficulty seeing even when wearing glasses?

3. Because of a physical, mental, or emotional condition, do you have serious difficulty concentrating, remembering, or making decisions?

4. Do you have serious difficulty walking or climbing stairs?

5. Do you have difficulty dressing or bathing?

6. Because of a physical, mental, or emotional condition, do you have difficulty doing errands alone such as visiting a doctor's office or shopping?

You can take issue with this questionnaire and observe that people might perhaps exaggerate. Who, for example, hasn't navigated a long flight of stairs and found himself rather fatigued at the end? Chronic obesity would tip the scales. At some point in the aging process, we all become disabled.