Development and content validity of the Person Experiences Interview Survey (PEIS): a measure of the mental health services experiences of people with developmental disabilities.

Purpose: People with developmental disabilities and mental health service experiences have a right to be included in healthcare decisions, including the evaluation of their mental health services and providers. However, few self-report measures address this need. This study aimed to fill this gap by developing and evaluating the content validity, including comprehension, relevance, and comprehensiveness, of the Person Experiences Interview Survey (PEIS) with people with developmental disabilities and mental health experiences.