PurposeProject complexity has been researched much. The majority of publication is searching for law-like relations or development of descriptive frameworks. More prescriptive knowledge is needed to guide the project managers in navigating the project complexity in project managers' pursuit of success. Identifying the complexities of a given project is a real-world problem for project managers (Mikkelsen et al., 2021). The purpose of the paper is to investigate the research of prescriptive knowledge on the management of project complexity.Design/methodology/approachBased on a longitudinally case study, this paper uses Action Design Research (Sein et al., 2011) (ADR) to research the management of project stakeholder complexity. ADR is a variation of action research (AR) with inspiration from design science (Hevner et al., 2004) where an artifact is designed to solve a real-world problem. In this case study, an information system was configured in collaboration with the project managers of the recipient organization.FindingsThe findings from the research project are presented using the affordance theory (Gibson, 1977) as a framing concept and give special attention the affordance perception (Pozzi et al., 2014). Among the project managers, who were very engaged in the co-design, the majority refrained from activating the information system and got the outside view from the stakeholders. Interviews afterward identified “fear of bad project ratings from the stakeholder” as the main course of resistance to deploy the surveying information system.Originality/valueThe paper contributes on two levels. The paper presents a novel approach to researching project complexity based on engaging the stakeholder in generating a common perception of the ongoing state of the projects. The paper also contributes insights into reasons for reluctance on the part of the participants (the project managers) of the recipient organization and hereby adds to the understanding of the organizational change aspect of AR in the research of project management. The paper concludes with the identified benefits of using ADR in research on project complexity management and gives recommendations for future research.