Responsiveness to Self-Report Interview Questions by Adults With Intellectual and Developmental Disability.

Researchers asked 11,391 adults with intellectual or developmental disability to answer interview questions about their lives. They wanted to know how many could give clear, scorable answers on their own. The team recorded whether each person spoke fluently or needed help, and how severe their disability appeared.

About six in ten adults gave answers that could be scored. People who spoke easily and had milder disabilities were far more likely to respond well. Many others gave all-or-nothing replies—either one-word answers or none at all.

Graves et al. (2016) later showed the same pattern in adults with Down syndrome; self-ratings on a health survey matched caregiver reports, but only when the adults could speak fluently. Son et al. (2013) found a warning sign: women with ID often said they had cancer screenings they never actually had, so self-report alone can mislead. Bakhtiari et al. (2021) added that youth with autism can self-report if their IQ is above 80 and they can pay attention—again linking success to ability level, not diagnosis.

Before you hand a client a questionnaire, watch how they talk. Fluent speech and mild ID predict usable answers. If the client gives short or random replies, switch to caregiver interview or simple yes-no checks. This quick screen saves time and keeps your data clean.