Overview

• Detlef Pollack and Gergely Rosta have published a substantially expanded 2025 edition of their standard work “Religion in der Moderne” with new data from Western and Eastern Europe, the Americas and Asia.
• The study documents a dramatic decline in religious belief and practice worldwide, overturning official affiliation figures in several countries.
• Nearly one-third of American adults now describe themselves as religiously unaffiliated after decades of single-digit rates.
• Weekly church attendance in Poland fell by ten percentage points between 2015 and 2021, and a recent online survey in Iran finds just 40 percent of respondents self-identify as Muslim.
• Russia remains an outlier, with rapid growth in Orthodox Church identification tied to rising national pride and cultural identity.