The Yearbook of International Religious Demography presents an annual snapshot of the state of religious statistics around the world. Every year large amounts of data are collected through censuses, surveys, polls, religious communities, scholars, and a host of other sources. These data are collated and analyzed by research centers and scholars around the world. Large amounts of data appear in analyzed form in the World Religion Database (Brill), aiming at a researcher’s audience. The Yearbook presents data in sets of tables and scholarly articles spanning social science, demography, history, and geography. Each issue offers findings, sources, methods, and implications surrounding international religious demography. Each year an assessment is made of new data made available since the previous issue of the yearbook.

The 2015 issue highlights both global and local realities in religious adherence, from the demographics of the world's atheists to the emigration of Christians from the Middle East. Other case studies include inter-religious marriage patterns in Austria, Muslim immigration to Australia, and methodological challenges in counting Hasidic Jews.