Cultural diversity beyond the binary – testing a disparity-weighted indicator of cultural classroom composition

Cultural classroom diversity is theorized to affect individual students through several mechanisms related to different diversity aspects. These include the number, relative size, and dissimilarity of cultural groups, not all of which are simultaneously captured by diversity measures currently established in educational contexts. Disparity-weighted measures, which quantify and incorporate differences between cultural groups, may offer a more comprehensive and valid operationalization of cultural diversity. This study adapts and tests the cultural fractionalization index CF from sociology, which accounts for similarities of cultural values between cultural groups. We examine CF in comparison to established diversity indicators using a longitudinal sample of 1560 students from 65 German secondary school classrooms. CF strongly correlated with established diversity indices but notably differentiated better between highly diverse classrooms, suggesting it captured additional information on cultural classroom composition. In exploratory multilevel analyses, we further compared CF to established measures in the common application of predicting individual students’ reading achievement. Results indicated significant negative effects of most diversity measures on reading achievement but a diverging pattern of results for CF, possibly reflecting its ability to correct overestimations of diversity inherent in established indices by including disparity. These findings highlight the potential of disparity-weighted indices like CF to advance research on the effects of cultural diversity and its potential underlying mechanisms. Our results emphasize the importance of a theory-driven definition of diversity and a deliberate choice of corresponding diversity measures.