However, in the overwhelming majority of countries, these religions are not specifically measured in censuses, large-scale surveys or population registers. For this reason, the study is limited to the eight major categories described above.Īs noted in previous Pew Research reports, some of the faiths that have been consolidated into the “folk religion” and “other religion” categories have millions of adherents around the world. 5 Beyond Christians and Muslims, cross-national demographic data on religious subgroups are generally not available. 4 For some countries with large Muslim populations, Pew Research has estimated the size of two main subgroups – Sunnis and Shias – but these are only approximations, expressed in ranges. For most countries, Pew Research was able to generate estimates for four main types of Christians – Catholics, Protestants, Orthodox and the remainder as an “other” category. 3 The main challenge in looking at religious diversity in this way is the serious data limitations for subgroups within religions other than Christianity. Some efforts to measure religious diversity have attempted to take into account subgroups of the major religious traditions. The remainder of the global population was consolidated into three additional groups: the religiously unaffiliated (those who say they are atheists, agnostics or nothing in particular) adherents of folk or traditional religions (including members of African traditional religions, Chinese folk religions, Native American religions and Australian aboriginal religions) and adherents of other religions (such as the Baha’i faith, Jainism, Shintoism, Sikhism, Taoism, Tenrikyo, Wicca and Zoroastrianism). In order to have data that were comparable across many countries, the study focused on five widely recognized world religions – Buddhism, Christianity, Hinduism, Islam and Judaism – that collectively account for roughly three-quarters of the world’s population. That study was based on a 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 staff and, in the case of European countries, by researchers at the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria.
The choice of which religious groups to include in this study stems from the original research that was done for “The Global Religious Landscape” report. 2 The closer a country comes to having equal shares of the eight groups, the higher its score on a 10-point Religious Diversity Index. It looks at the percentage of each country’s population that belongs to eight major religious groups, as of 2010. This study, however, takes a relatively straightforward approach to religious diversity. Each of these approaches can be applied to the study of religious diversity. Social scientists have conceived of diversity in a variety of ways, including the degree to which a society is split into distinct groups minority group size (in share and/or absolute number) minority group influence (the degree to which multiple groups are visible and influential in civil society) and group dominance (the degree to which one or more groups dominate society). As part of the next phase of this project, Pew Research has produced an index that ranks each country by its level of religious diversity.Ĭomparing religious diversity across countries presents many challenges, starting with the definition of diversity. Several years ago, the Pew Research Center produced estimates of the religious makeup of more than 200 countries and territories, which it published in the 2012 report “ The Global Religious Landscape.” The effort was part of the Pew-Templeton Global Religious Futures project, which analyzes religious change and its impact on societies around the world.