Secondary education as a protective factor against child marriage in Indonesia: evidence from the 2012 and 2017 Demographic and Health Surveys

Child marriage remains a persistent public health and development challenge in Indonesia, with over one million women aged 20–24 reported to have entered unions before the age of 18. This study employs data from the 2012 and 2017 Indonesia Demographic and Health Surveys (IDHS), the most recent nationally representative waves available, to examine the protective role of secondary education and socioeconomic conditions on early marriage. A pooled, repeated cross-sectional analysis was conducted among women aged 20–24, using survey-weighted logistic regression and doubly robust inverse probability weighted regression adjustment (IPWRA), with nearest-neighbor propensity score matching as a sensitivity check. The results show that completing secondary education reduces the probability of early marriage by 19.3% points in 2012 and by 26.9% points in 2017, indicating a strengthening of the protective association over time. Wealthier households and urban residences were also negatively associated with early marriage, while smaller household sizes were associated with higher risk. Despite improved educational attainment over the period, overall prevalence declined only marginally from 16.98% to 16.34%, suggesting that structural and cultural factors continue to constrain aggregate progress. This study is descriptive and quasi-experimental in nature; the findings reflect strong, policy-relevant associations rather than pure causal effects, as unobserved confounding cannot be fully ruled out in a cross-sectional framework. Although the data predate the 2019 Marriage Act amendment, the patterns identified remain broadly consistent with more recent Indonesian and international evidence. These findings underscore secondary education as a critical protective factor against child marriage and highlight the need for complementary interventions in legal enforcement, poverty reduction, and community norm change to achieve meaningful reductions in prevalence.