Basic activities of daily living (ADL) is a composite measure of disability, measured with the Katz Activities of Daily Living Scale. The scale measures six basic physical abilities: walking across a small room, bathing, dressing, eating, getting from bed to chair, and toileting.

Participants are asked to report need for help/assistance in performing the ADLs. Responses are then dichotomized into 0 = no help and 1 = requires help or unable to do (see below). The composite measure ranges from 0 to 6 and is the sum of the number of items for which participants report the need for help/assistance, with higher scores indicating greater disability.

Participants are asked the following six questions:

Do you need help, either from another person or a special equipment or device...

1. walking across a small room?
2. bathing, either a sponge bath, tub bath or shower?
3. dressing, like putting on a shirt, buttoning and zipping, or putting on shoes?
4. eating, like holding a fork, cutting food, or drinking from a glass?
5. getting from a bed to chair?
6. using the toilet?

Response choices for each item: