Religion includes affiliation, belief, practice, tradition, and organizational participation. Attendance can connect people to social networks and political messages; theology and group history can shape issue priorities. People sharing an affiliation can differ by race, region, generation, and frequency of practice. A category such as "religious" is therefore too broad to explain a vote without a specified measure and mechanism.

Region captures overlapping political environments: economic structure, urbanization, migration, racial composition, media markets, institutions, and party history. A regional association may change as populations and coalitions change. Residence can shape experience, while politically like-minded people may also choose where to live.

Video lesson: How Voters Decide: Crash Course Government and Politics #38