Multidimensional Heterogeneity: Conceptual Foundations and Measurement Strategies

Heterogeneity is a key contextual factor shaping social structure, inequality, and cohesion. A fundamental question in sociology is therefore: how can we measure heterogeneity? Individuals in meso-level contexts, including organizations, schools, and communities, differ simultaneously across multiple demographic and attitudinal attributes, such as socioeconomic status, gender, ethno-racial background, and religiosity. These differences can overlap or cut across each other. Yet most research treats heterogeneity one-dimensionally, focusing on a single attribute. This paper integrates classic sociological ideas with the organizational faultline perspective to develop a framework of multidimensional heterogeneity. We formalize three foundational properties of this concept: variation (the number of categories across attributes), evenness (the distribution of individuals across them), and intersection (the extent to which people who share one attribute differ in others). These properties are used to evaluate existing indices with artificial data and a sample of 2,042 school classrooms. Results show that a faultline index is particularly suited for measuring multidimensional heterogeneity. By clarifying what indices measure and guiding researchers in selecting those that fit theoretical concerns, this paper advances research on diversity, cohesion, and stratification.