Purpose This paper aims to share a practical evaluation tool intended to guide and support the participation of older people in PAR projects. Participatory action research (PAR) studies with older adults have been increasing over the past ten years. Scientific evidence provides key principles for PAR projects to achieve meaningful participation by older people; however, respecting the ideals of PAR is not always straightforward. Design/methodology/approach This paper presents a case study that evaluated the involvement of nonacademic researchers in a PAR project using an evaluation tool derived from a literature review of PAR undertaken with this population (Corrado et al., 2020). The study goals were first to assess the assets and limits of the older co-researchers' participation within the PAR project, and second to provide a revised version of the evaluation tool to support future PAR with older people. First, the authors designed an evaluation tool for nonacademic participation in PAR studies by older people that covers three main themes: older people positioned as prominent research partners; symmetrical power relations between academic and nonacademic researchers; and commitment regarding inclusiveness and long-term collaboration. Second, the authors performed an evaluation using this tool within the Active Aging with Dignity PAR Project. Findings Third, the authors used the results of this experiment to suggest improvements for an enhanced version of the evaluation tool aiming at supporting fuller involvement of older nonacademic researchers in PAR studies. Originality/value To the authors' knowledge, this evaluative tool is a methodological innovation in gerontology.