The information systems literature frequently models project performance of information systems projects as a function of user participation. Markus and Mao (2004) consolidate the literature on user participation in a theoretical framework and call for its instantiation and empirical investigation. In this study, we answer this call by using meta-analytic structural equation modeling to fit the framework to a meta-analytic sample of 226 studies with a total of 42,330 information systems projects. We instantiate the original framework in three important ways. First, we differentiate between capacities and capabilities of project stakeholders to include users. Second, we differentiate between formal and informal mode of user participation. Third, we include residual risk as an important factor in the relationship between user participation and project performance. Our results offer support but also a nuanced perspective on the theoretical framework by Markus and Mao (2004) of user participation and suggest new directions for future research. User participation is necessary to improve project outcomes but not sufficient to ensure project outcomes.