The project aims to answer the following research question: What explains the success of transitional justice (TJ)? Findings in this field have been inconclusive partly due to the quality of existing datasets at three levels: inadequate unit of analysis (country); absence of data to measure TJ outcome; lack of contextual/control variables. This project offers to build a new large dataset covering European, Latin American, African and Asian countries that experienced transitions from authoritarianism and/or conflict situations. A second dataset will be created to measure TJ outcome through expert surveys. The two new sets will enable us to answer the research question through a two-step strategy: first, the development of a TJ typology; second, the identification of explanatory factors through statistical analysis. This original dataset will offer an important theoretical contribution and be available in open access. An Observatory will be created to monitor developments in TJ worldwide.