Measuring disparities in the incidence of sexually transmitted diseases.

The Centers for Disease Control and Prevention (CDC) defines a health disparity as a "[health] difference that occurs by gender, race or ethnicity, education or income, disability, geographic location, or sexual orientation." Health equity is achieved by eliminating health disparities or inequalities. Measuring health disparities is a critical first step toward reducing differences in health outcomes. To determine the methods to be used in measuring a health disparity, several decisions must be made, which include: (1) selecting a reference group for the comparison of 2 or more groups; (2) determining whether a disparity should be measured in absolute or in relative terms; (3) opting to measure health outcomes or health indicators expressed as adverse or favorable events; (4) selecting a method to monitor a disparity over time; and (5) choosing to measure a disparity as a pair-wise comparison between 2 groups or in terms of a summary measure of disparity among all groups for a particular characteristic. Different choices may lead to different conclusions about the size and direction of health disparities at a point in time and changes in disparities over time.The objective of this article is to review the methods for measuring health disparities, provide examples of their use, and make specific recommendations for measuring disparities in the incidence of sexually transmitted diseases (STDs).