Abstract
We examine the strengths and weaknesses of different “absence measures” scholars use to classify individuals as religious or nonreligious. Drawing on a novel dataset with data from eight countries (Argentina, Australia, Brazil, Canada, Finland, Norway, the UK, and the USA), we analyze how many people would be considered nonreligious based on four common measures: religious affiliation, religious service attendance, belief in a monotheistic god, and self-reported religiosity. We find that different measures lead to substantially different estimates of the number of nonreligious people in a country. The single measure that identifies the highest percentage of nonreligious people is never attending religious services, while the measure that identified the lowest percentage was those who report they are not at all religious. We also show that self-reported religiosity is a stronger predictor of attitudes toward religion than the other measures. Our findings suggest that scholars need to consider carefully the implications of using different measures of nonreligion, as this decision can have a meaningful impact on research findings.