A Summary Measure of Health Disparity

OBJECTIVES: Eliminating health disparities is a goal of Healthy People 2010. In order to track progress toward this goal, we need improved methods for measuring disparity. The authors present the Index of Disparity (ID) as a summary measure of disparity. METHODS: The ID, a modified coefficient of variation, was used to measure disparity across populations defined on the basis of race/ethnicity, income, education, and gender. Disparity was also assessed for a diverse range of health indicators and over time to monitor trends. RESULTS: Disparity in cardiovascular disease deaths decreased based on gender from 1989 to 1998 but was largely unchanged based on race/ethnicity. The magnitude of disparities in cervical cancer and cholesterol screening, smoking, exercise, and health insurance ranged from 1.9% to 78.6%. The largest disparities for health indicators were not associated with any particular population classification, whether defined on the basis of race/ethnicity, education, or income. CONCLUSIONS: To eliminate disparities, we need a means to assess disparities across many types of health indicators. Furthermore, for a given health indicator, disparities may differ for populations defined on the basis of race/ethnicity, education, income, and so on. The ID is a simple method for summarizing disparities across groups within a population that can be applied across health indicators regardless of magnitude, over time to monitor trends, and across different populations.