Measuring the world Muslim population

Brian J. Grim, Pew Forum on Religion & Public Life, and Boston University
Becky Hsu, Princeton University

This paper describes and evaluates estimates of the world Muslim population developed by researchers at Boston University’s Institute for the Study of Culture, Religion and World Affairs. Boston University’s World Religion Database (WRD) contains statistics on Muslim affiliation for every country of the world and provides estimates down to the province level for numerous countries. It provides source material, including national censuses, demographic surveys and public opinion surveys, as well as ethnographic ‘best estimates’. This paper discusses the documentation on survey types and coverage as well as the methods used to make estimates. This paper shows that despite many practical difficulties, it is possible to make estimates of Muslim populations for most countries of the world today. The data are available to through research libraries in the WRD (www.WorldReligionDatabase.org), launched in October 2008.