The proposed AHRC-NSF Collaborative Funding Opportunity between Leigh Payne (University of Oxford) and Kathryn Sikkink (University of Minnesota) aims to develop an empirically-tested theory of transitional justice (i.e., human rights trials, truth commissions, and amnesties) to explain its impact on human rights and democracy. It also strives to develop a corresponding set of policy recommendations to achieve those political goals. The collaborators' prior research qualifies them for this project. Each has published widely on violence, human rights, and democratization. They recently formed separate research teams to develop large-N, cross-national data bases on transitional justice mechanisms. Both teams confirmed for the first time that transitional justice has a positive impact on human rights and democracy. Contradictory findings from their research, however, have motivated them to collaborate to develop a new project that further improves understanding of transitional justice. The proposed project will construct a new data set that merges their existing data, adds newly collected and refined data on transitional justice mechanisms, and employs a mixed-method approach to explain the success of transitional justice in achieving its political objectives. Quantitative research, utilizing propensity scores and matching techniques, will allow the researchers to make inferences from the large-N data set while qualitative research, specifically fuzzy set qualitative comparative analysis (fs QCA), process-tracing, and the case study method, enables the team to identify combinations of conditions and/or multiple causal pathways for positive or negative effects on democracy and human rights. Intellectual Merit. The proposed project will build the first empirically-tested theory of when, why, and how transitional justice achieves human rights and democracy goals. It will derive and test assumptions from four theoretical approaches: enforcement and deterrence, norms and socialization, rule of law, and accountability with stability. The first three focus on the role of trials in bringing positive political change, a mechanism identified by both research teams as crucial to transitional justice success. The fourth approach examines how combinations of mechanisms (i.e., trials and amnesties or trials, amnesties, and truth commissions), findings from Payne research, achieve these positive results. Based on these theoretical approaches and previous findings, the collaborative team has created a research design that will allow them to make an important theoretical contribution to the study of transitional justice, human rights, and democratization. They will present their findings at international scholarly conferences and publish scholarly articles to advance academic debate in an under-theorised field. Broader Impacts. First, the study will advance transitional justice policy. The project identifies the specific types and combinations of mechanisms and contextual factors (i.e., political and economic conditions, judicial institutions, and political agency) that enhance the likelihood of success of transitional justice. The researchers will produce a policy blueprint and present their findings to policy-makers at conferences and meetings, disseminate them to relevant organisations, and make them publicly available on their website. The collaborative project emerges from a creative method for resolving contradictory findings in the researchers' previous work. Rather than using their different findings to carve out separate and competing projects, the researchers have chosen to collaborate to achieve important theoretical and policy goals. Second, the collaborators will build an institutional partnership between the Oxford Transitional Justice Research program and the University of Minnesota's Transitional Justice Research Collaborative, in which both researchers play leading roles, to maintain the data set and encourag