The Pew Research Center recently published an interesting “religious diversity index,” which I have re-mapped (below). (Pew’s own map, also posted below, is in my view inadequate.) As can seen on either map, the lowest levels of religious diversity are generally found in the heavily Muslim belt of northern Africa and southwestern Asia. Exceptions are encountered here in countries that have large numbers of foreign workers, such as the United Arab Emirates (UAE). Different patterns would have resulted if only citizens had been counted: some 74–76% of the residents of the UAE are Muslim, but virtually all UAE citizens (Emiratis) adhere to the faith. Low levels of religious diversity are also found in a few predominately Christian countries (Romania, Moldova, Papua New Guinea) and in one Buddhist country (Cambodia).
High levels of religious diversity are found in several parts of the world. Most prominent are wealthy Western countries with large numbers of immigrants and many residents with no religious adherence. The northern and eastern countries of sub-Saharan Africa where Christianity and Islam coincide also rate high in the religious diversity index. In eastern Asia, Japan, South Korea, Taiwan, and Vietnam have high diversity scores, due largely to their combinations of Buddhism, secularism and, especially in South Korea, Christianity. Malaysia ranks high due mostly to the religious diversity of its Chinese population. For the same reason, Singapore has the world’s highest ranking, and by a considerable margin. I had thought that Suriname would come out on top, with its Christian, Muslim, Hindu, and animist communities, but it falls into second place. Neighboring Guayana and French Guiana also have high religious diversity rankings (but I mapped French Guiana as part of France, as it is an integral department of that country).
Overall, the Pew Religious Diversity Index is meaningful and well-formulated, which is why I decided to remap it. But I do have some criticisms. The first is its failure to include diversity within the major religious traditions. Hinduism, for example, is so diverse that some scholars view it more as a family of related faiths than as a single religion. Buddhism, Christianity, and Islam also have considerable internal diversity of beliefs and practices. The gap in Turkey (Türkiye) between Sunni Islam and Alevism is especially large, and if it had been considered, the country would have been given a higher diversity score. By the same token, Tonga would have ranked higher if members of the Church of Jesus Christ of Latter-Day Saints (Mormons) had been separated from Trinitarian Christians.
Another problem, which is probably insurmountable, stems from the failure to consider religious syncretism and other combinations of faith traditions. Papua New Guinea, for example, is overwhelmingly Christian on the surface, and thus has a low diversity ranking. But most Papuans strongly retain elements of their traditional beliefs, which are themselves very diverse. Other countries have similar mixtures. A scholar who worked in the west African country of Guinea once told me that the first thing you need to understand about the country is the fact that it is 90 percent Muslim and 90 percent animist. A similar issue is encountered in Japan, where most people are relatively secular but still maintain some Buddhist and Shinto beliefs and practices.
Putting all faiths other than Christianity, Islam, Hinduism, Buddhism, and Judaism into a single “other religions” category is another problem, although it is again one that is difficult to avoid. Chinese “folk religion” (religions?) supposedly has several hundred million adherents. It is also notable that Sikhism is lumped together with “other religions,” even though it has roughly twice as many adherents as Judaism.
As a final note, the Pew Religious Diversity Index is derived from sophisticated statistical analysis, which is explained on the website. The following passages outline the methodology employed:
Two factors determine a country’s religious diversity score: the extent to which its population falls into a single religious group, and the degree to which the remaining population is dispersed across other religious categories. When a single religious group constitutes a higher proportion of the population, the country receives a lower RDI score.
Meanwhile, among countries where the largest group comprises the same share of the population, places in which the remaining population is distributed more evenly across groups score higher on the RDI. For example, in a country in which 70% of the population belongs to a single religious group, the index score would be 4.9 if the remaining 30% were concentrated in just one category. However, the score would rise to around 5.7 if the remainder were spread evenly across five or six different groups