Equity monitoring for social marketing: use of wealth quintiles and the concentration index for decision making in HIV prevention, family planning, and malaria programs

BACKGROUND The majority of social marketing programs are intended to reach the poor. It is therefore essential that social marketing organizations monitor the health equity of their programs and improve targeting when the poor are not being reached. Current measurement approaches are often insufficient for decision making because they fail to show a program's ability to reach the poor and demonstrate progress over time. Further, effective program equity metrics should be benchmarked against a national reference population and consider exposure, not just health outcomes, to measure direct results of implementation. This study compares two measures of health equity, concentration indices and wealth quintiles, using a defined reference population, and considers benefits of both measures together to inform programmatic decision making. METHODS Three datasets from recent cross-sectional behavioral surveys on malaria, HIV, and family planning from Nepal and Burkina Faso were used to calculate concentration indices and wealth quintiles. Each sample was standardized to national wealth distributions based on recent Demographic and Health Surveys. Wealth quintiles were generated and concentration indices calculated for health outcomes and program exposure in each sample. Chi-square and t-tests were used to assess statistical significance of results. RESULTS Reporting wealth quintiles showed that recipients of Population Services International (PSI) interventions were wealthier than national populations. Both measures indicated that desirable health outcomes were usually concentrated among wealthier populations. Positive and significant concentration indices in all three surveys indicated that wealth and program exposure were correlated; however this relationship was not necessarily linear. In analyzing the equity of modern contraceptive use stratified by exposure to family planning messages in Nepal, the outcome was equitable (concentration index = 0.006, p = 0.68) among the exposed, while the wealthy were more likely to use modern contraceptives (concentration index = 0.071, p < 0.01) among the unexposed. CONCLUSIONS Using wealth quintiles and concentration indices together for equity monitoring improves usability of findings for decision making. Applying both metrics, and analyzing equity of exposure along with health outcomes, provides results that have statistical and programmatic significance. Benchmarking equity data against national data improves generalizability. This approach benefits social marketers and global health implementers to improve strategic decision making and programs' ability to reach the poor.