AbstractEvaluation plays a pivotal role in transdisciplinary (TD) research, often discussed during funding stages or when assessing project impacts. A few studies delve into the participant perspective when examining the quality of transdisciplinarity. Our work contributes to this area of assessment. Rather than providing a definitive definition of transdisciplinarity, we developed a questionnaire to evaluate a set of TD principles within a specific TD initiative. We collected insights from 100 individuals out of a pool of 200 participants engaged in a TD initiative since 2016. Given the long-term nature of the case study, our sample included both frequent and occasional participants. Using non-parametric statistical, we concluded that frequent participants express higher satisfaction with their involvement, identify more outcomes stemming from their participation, and assign greater importance to TD principles. These findings highlight the significant impact of investing in long-term TD initiatives. Additionally, our questionnaires featured open-ended questions to capture participants’ individual definition of the initiative, along with their perceived benefits and drawbacks. Through content analysis, we identified two distinct discourses: positivism and postpositivism. The positivist discourse predominantly features male participants over 60 years of age, primarily from the research community. These participants express lower satisfaction with their participation and assign less value to TD principles. We found no association between positivism/postpositivism and participation frequency (i.e., frequent/casual). This suggests that these two discourses can coexist and interact within a TD environment. Nevertheless, the perceived value of TD is not uniform across these groups, indicating that TD may not align with everyone’s objectives, even in complex contexts where the approach is considered essential.