About the Data


Data Sources

The Global Religious Futures project is based on data obtained using a range of social science methods, including public opinion surveys, demographic analysis and coding. The Pew Research Center's Religion & Public Life project has conducted public opinion surveys in more than 40 countries, completed demographic analyses that cover 234 countries and territories, and coded 198 countries and territories for government restrictions on religion and social hostilities involving religion. Additional data sources – such as the United Nations – are cited where used.

Defining Religious Groups

The Global Religious Futures project is based on religious self-identification. For survey questions, data are reported for different religious groups. Religious affiliation is determined based on a respondent's answer to the following question: What is your present religion, if any? Are you [response options are modified by survey country]? Demographic analyses estimate the number of people around the world who view themselves as belonging to various religious groups. This includes people who hold beliefs that may be viewed as unorthodox or heretical by others who claim the same religion. The demographic analyses do not attempt to measure the degree to which members of these groups actively practice their faiths or how religious they are.

The Global Religious Futures website contains data on the size and distribution (and opinions, where data is available) of five widely recognized world religions - Christians, Muslims, Hindus, Buddhists and Jews - as well as the religiously unaffiliated. It also looks at followers of folk religions, including African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religions. The "Other Religions" category includes Bahai’s, Jains, Sikhs, Shintoists, Taoists, followers of Tenrikyo, Wiccans, Zoroastrians and many other faiths.

Defining Regions

The Global Religious Futures project breaks the world into six major regions for comparisons: Asia and the Pacific, Europe, Latin America and the Caribbean, the Middle East and North Africa, North America and sub-Saharan Africa. For a list of countries in each region, see the methodology section from “The Global Religious Landscape” report. These region assignments may differ from the regional groupings used in individual Pew Research Center reports.

Survey Methodology

The Pew Research Center employs a rigorous methodology for its public opinion surveys. Read a full description of the methodologies employed in each survey that feeds the Global Religious Futures project:

Methodology for Demographic Analyses

The Pew Research Center’s world population studies are based on a rigorous country-by-country analysis of data from more than 2,500 national censuses, large-scale surveys and official population registers that were collected, evaluated and standardized by Pew Research Center staff. Read a full description of the methodology employed in the April 2015 report “The Future of World Religions: Population Growth Projections, 2010-2050,” which feeds the Global Religious Futures project.

The Pew Research Center’s study of global migration also is based on census and survey data from countries around the world. Read a detailed description of the methodology employed in the March 2012 report “Faith on the Move,” which feeds the Global Religious Futures project.

Methodology for the Global Restrictions on Religion Studies

The Pew Research Center’s Global Restrictions on Religion studies use two indexes to rate countries and territories on their levels of restrictions. The Government Restrictions Index (GRI) measures – on a 10-point scale – government laws, policies and actions that restrict religious beliefs or practices. The GRI is comprised of 20 measures of restrictions, including efforts by governments to ban particular faiths, prohibit conversions, limit preaching or give preferential treatment to one or more religious groups. The Social Hostilities Index (SHI) measures – on a 10-point scale – acts of religious hostility by private individuals, organizations and social groups. This includes mob or sectarian violence, harassment over attire for religious reasons and other religion-related intimidation or abuse. The SHI includes 13 measures of social hostilities.

Read a full description of the methodology employed in the February 2015 report “Latest Trends in Religious Restrictions and Hostilities,” which feeds the Global Religious Futures project.

Rounding and Statistical Significance

Survey data are rounded to whole percentages, and figures may not add exactly due to rounding. When comparing results across countries, religious groups or other demographic groups, it is important to note that apparent differences may not be statistically significant. Pew Research Center reports include statements about the margin of error for different groups surveyed or measures coded. Refer to the individual report methodologies for more information.

For all demographic data, percentages are calculated from unrounded numbers. Figures may not add exactly due to rounding. Populations of less than 10,000 are shown as <10,000. Populations of 10,000 and more are rounded to the nearest 10,000.