Abstract
This paper examines three dimensions of American religion--belonging, behavior and belief--by creating a single, unified scale of religiosity and testing it with the American Religious Identification Survey (ARIS) and the General Social Survey (GSS). It shows that certain combinations of those three variables are far more common than others, and demonstrates changes over time in the percentage of people belonging to each cluster, with a trend toward diminishing religiosity. The paper identifies socio-demographic and geographic factors that are associated with the religiosity cluster to which a person belongs. The paper examines the ability of the new scale to predict how people will answer questions on contentious societal issues, using belief in evolution as a case study. The most religious definitely reject human evolution while the most secular definitely believe in it.