Older People's External Residential Assessment Tool (OPERAT): a complementary participatory and metric approach to the development of an observational environmental measure.

Participatory approaches to research and robust statistical testing are not mutually exclusive. OPERAT can be used to assess the suitability of external residential environments for older people with different physical and cognitive capacities, living in rural or urban areas. OPERAT can be used to help plan residential environments that are friendly for all ages.