Validity evidence for self-report with assistance to measure physical activity behavior in adults with intellectual disabilities.

Marquell and colleagues asked adults with intellectual disability to talk about their weekly exercise.

A helper read each question aloud and wrote down the answer.

The team then compared these answers to step counts from pedometers and accelerometers the adults wore.

The helper-assisted interviews matched the device data well.

The study showed high reliability and moderate to strong validity for this simple interview method.

Lecavalier et al. (2006) warned that plain Likert scales fail for most adults with ID unless you add pictures and keep the disability level mild.

Marquell’s team side-stepped this problem: they used spoken questions and a helper, so even adults with moderate ID could take part.

Johnson et al. (2009) had already proven that three days of pedometer data gives a solid picture of weekly steps in the same population; Marquell now shows you can get equally solid data just by asking, as long as someone gives a gentle assist.

Guerra-Balic et al. (2015) validated the six-minute walk test for mobility in adults with ID; together these papers give you three cheap tools—interview, pedometer, and walk test—to measure activity without lab gear.

You can trade expensive devices for a ten-minute assisted interview.

Use the script from the paper, let the client pick easy words like “a little” or “a lot,” and record answers on the spot.

Pair the interview with a quick pedometer check on day one and day three to keep everyone honest; if numbers line up, you can fade the devices and just talk.