Major Religious Groups - Religious Demographics

Religious Demographics

Further information: List of religious populations Main category: Religious demographics

One way to define a major religion is by the number of current adherents. The population numbers by religion are computed by a combination of census reports and population surveys (in countries where religion data is not collected in census, for example the United States or France), but results can vary widely depending on the way questions are phrased, the definitions of religion used and the bias of the agencies or organizations conducting the survey. Informal or unorganized religions are especially difficult to count.

There is no consensus among researchers as to the best methodology for determining the religiosity profile of the world's population. A number of fundamental aspects are unresolved:

• Whether to count "historically predominant religious culture"
• Whether to count only those who actively "practice" a particular religion
• Whether to count based on a concept of "adherence"
• Whether to count only those who expressly self-identify with a particular denomination
• Whether to count only adults, or to include children as well.
• Whether to rely only on official government-provided statistics
• Whether to use multiple sources and ranges or single "best source(s)"