The World Religion Dataset, 1945-2010: Logic, Estimates, and Trends

This study introduces a new dataset on world religions. The World Religion Project consists of (a) a systematically developed classification of major world religions and religious families within major world religions, which enabled (b) the collection of data on the distribution of the population of all states in the international system across these religious categories, over the period of 1945-2010, and (c) a set of methods to reconcile among conflicting data from multiple sources, to deal with missing data, and to integrate multiple figures for a given observation. In the present study we discuss the significance of the World Religion Project, its internal logic and the development of the religion tree system of classification, and the data collection and data management process. We then provide a number of descriptive statistics about national, dyadic, regional, and global distributions of world religions, as well as some preliminary relationships between the religious similarity of states and their regime type, alliance patterns, and propensity to conflict. We discuss the potential contribution of this dataset to the study of the relationship between religion and international conflict and cooperation.