Religion (RCMS)

The evolution of the religious landscape in the United States is documented through several key datasets. The earliest, from 1980, was compiled by the Glenmary Research Center and covers 111 Judeo-Christian church bodies, providing insights into church numbers and adherents at that time. However, it excludes most historically African American denominations and other faith traditions, limiting its scope.

In 1990, the Association of Statisticians of American Religious Bodies (ASARB) conducted a broader survey, encompassing 132 religious groups. This dataset expanded coverage to include categories like total population, all religions, major religions, evangelical, mainline, and other congregations.

The 2000 survey by ASARB further widened its scope, covering 149 religious groups and offering a comprehensive view of religious affiliation at the turn of the millennium. Yet, it still lacked complete data on historically African American denominations.

Significant advancements came with the 2010 and 2020 ASARB surveys, which adopted a more inclusive approach. These newer surveys retained the core categories from previous years while adding more detailed metrics, such as black Protestant, Catholic, and Orthodox Christian congregations. This expanded range provides a more nuanced understanding of the United States' religious composition, capturing the dynamics of a broader array of religious traditions and communities.

Despite some limitations, such as underrepresentation of smaller groups, these datasets collectively offer a valuable longitudinal perspective on religious trends in the United States. They enable the tracking of changes in church membership, the growth or decline of specific denominations, and shifts in the overall religious landscape over time.