The Measurement of Ethnic and Religious Divisions: Spatial, Temporal, and Categorical Dimensions with Evidence from Mindanao, the Philippines

An ever-expanding body of empirical research suggests that ethno-religious divisions adversely impact a host of normatively desirable objectives linked to the quality of life in society, implicitly representing a strong challenge to multiculturalist theory and policies. The appropriate conceptualization and measurement of ethno-religious divisions has consequently become the subject of complex methodological debate. This article unpacks some of this complexity and provides a synthetic critique of how eight key measures each capture the notion of divisions and relate to each other conceptually, theoretically, and empirically within a divided society. It explores simple proportions, fractionalization, polarization, cultural distance, segregation, cross-cuttingness, horizontal inequality, and intermarriage indicators. Furthermore, instead of presenting national-level temporal snapshots of divisions as in much work, it purposely examines how measures also perform at more localized levels of analysis and over time, drawing on individual-level census data from one deeply-divided society, Mindanao, in the Philippines. Analysis underscores four major issues to which researchers should pay more attention: the sensitivity of measures to (1) the underlying causal mechanisms linking divisions with outcomes; (2) the social forces and methodologies shaping the identification and categorization of groups; (3) the passage of time and evolution of divisions; and (4) the level of spatial analysis. The article provides practical guidance and discusses the key implications of these points both for quantitative scholars working with these measures and for qualitatively-inclined empiricists and normative theorists wishing to interpret, evaluate, or otherwise engage the quantitative research on the merits and demerits of diversity.