Measuring religious commitment among Catholics and Protestants: A new approach

Researchers using survey data to study religious commitment often create additive indices in which respondents receive a "point" on the scale for each behavior in which they engage, implicitly assuming that each activity is equally normative in each religious tradition. This has led some scholars to suggest that these scales can be "biased" in favor of evangelicals. In this paper, we introduce a unique series of survey questions asking respondents how important various activities are "for people of your religion." We use these new measures to generate tradition-specific weights for each component of a religious commitment scale according to the activity's perceived importance. We then present a method for constructing scales when such "importance" items are not available, using the frequency of behavior within each religious tradition as a surrogate for Importance. We find that constructing religious commitment scales that take into account the normative differences across religious traditions produces statistically significant differences in the levels of commitment by religious tradition, especially among Roman Catholics. However, the substantive significance is less evident. When various measures of religious commitment are included as independent variables in multivariate models of political attitudes, their performance is remarkably similar. It appears that the standard additive indices of religious commitment commonly utilized by scholars of religion and politics are adequate for most analyses of social and political attitudes.