Patient participation is a highly valued principle. Yet, it remains difficult both to achieve it and to assess its added value, as participation is often started without much clarification of what it means or aims to do. In theory, patients may be invited to participate for reasons of democracy, empowerment, knowledge integration and instrumentalism. By making these rationales explicit in a participatory practice in the Netherlands, we aimed to contribute to the long-needed 'clarity through specificity' in participation. Apart from the rationales, our analytic framework included dimensions of the participatory process, reflected by questions like 'Who participates?', 'In what?' and 'With how much control?' We used this framework to conduct and analyse semi-structured interviews (n = 51) with patient participants (20), professionals (14) and researchers (17). We found that the participatory practice included all rationales and that the actual manifestation of an intended rationale very much depended on the design of the dimensions of the participatory process. We conclude that invited participation may gain in clarity by making explicit the rationales for participation. If put at the centre of attention, and made the leading factor in the design of the dimensions of the participatory process, explicit rationales may support the realisation of participation in practice and prevent it from resulting in mere window-dressing.
