Wealth-related inequality in child marriage in India using decomposition analysis

Despite a declining national trend, child marriage remains an important public health and developmental concern in India. This study examined wealth-related inequality in child marriage and the statistical contributions of selected socio-demographic characteristics using nationally representative data from the fourth (NFHS-4, 2015–16; n = 122,955) and fifth (NFHS-5, 2019–21; n = 118,700) rounds of the National Family Health Survey (NFHS) among women aged 20–24 years. Wealth-related inequality was measured using the Erreygers Concentration Index (ECI), and regression-based decomposition was used to assess the contributions of selected characteristics to the observed inequality. Child marriage prevalence declined between the two survey rounds, but remained concentrated among economically disadvantaged women. The ECI was negative and statistically significant in both rounds, changing from − 0.281 (95% CI: − 0.289 to − 0.273) in NFHS-4 to − 0.257 (95% CI: − 0.265 to − 0.249) in NFHS-5. The absolute wealth gap narrowed from 20.65 to 19.04% points, whereas the poor-to-non-poor prevalence ratio increased from 2.07 to 2.20. Substantial differences in wealth-related inequality were also observed across states and Union Territories. Educational attainment made the largest statistical contribution to the explained component of inequality, accounting for 77.06% in NFHS-4 and 77.41% in NFHS-5. Place of residence was the second-largest contributor in NFHS-4, while the contribution of mass media exposure increased substantially in NFHS-5. The findings indicate that reductions in child marriage have not been accompanied by equivalent reductions in socioeconomic inequality. Policies that support girls’ secondary education, improve access to information, strengthen social protection, and prioritize economically disadvantaged households may help promote more equitable progress towards eliminating child marriage.