Evaluating health disparities in the Healthy People 2010 Final Review: Methods and statistics

The second overarching goal of Healthy People 2010 is to eliminate health disparities by race and ethnicity, gender, education, income, geographic location, disability status, or sexual orientation. This goal applies to all population-based objectives included in Healthy People 2010. We provide an in-depth look at the methods and statistics used to measure and evaluate health disparities in the Healthy People 2010 Final Review, the decade's final assessment of progress toward Healthy People goals and objectives. Data from the cancer focus area are used to illustrate the calculation and interpretation of disparity statistics at the most recent data point and changes in disparities over the past decade. Analytic issues considered in the development of these disparity measures will be explained, including the selection of the reference group, measurement of absolute or relative differences, and consideration of favorable or adverse events. Pair-wise and summary statistics used to measure disparity between population subgroups, including the percent difference and the index of disparity, are described, and the interpretation of these statistics is stressed. Methods for testing the statistical significance of disparities at a single point in time and the change in disparities over time are also discussed. Lastly, we describe potential changes in the measurement of health disparities for the latest iteration of national health objectives, Healthy People 2020.