The role of people with intellectual disability in intellectual disability research: A systematic review of Delphi studies.

The design of intellectual disability research warrants critical examination, as the knowledge produced through these approaches informs evidence-based practices. People with lived experience should be recognised as experts in understanding their own bodies, conditions, and treatment. This systematic review examined the design of Delphi studies to assess the extent to which people with intellectual disability are included as experts. The Delphi method, which gathers structured feedback from experts, offers insight into how lived experience is valued as a source of knowledge. Across fifty-five publications reporting on forty-nine separate Delphi studies that met our inclusion criteria, only nine involved people with intellectual disability directly. In contrast, family and informal caregivers were more frequently represented as experts, and their perspectives carried greater influence. The findings of this review include guidance for practitioners and researchers to facilitate greater participatory roles of people with intellectual disability.