Legal reforms, norms, and child marriage: observational evidence on behavioral responses in sub-Saharan Africa

• We take a macro perspective on age-of-marriage reforms in Sub-Saharan Africa (SSA). • We study 88 age-of-marriage law changes in 38 countries and child marriage rates. • Legal texts are not enough of a shock to stop practicing child marriages. • Mismatch between multitude of legal texts (not uniform) and child marriage trends. • Mismatch between formal and informal marriage allowing for behavioral adaptations. This study takes a macro perspective to examine how age-of-marriage laws have evolved across countries in Sub-Saharan Africa, and how societal norms and behavior related to child marriage changed concurrently. The literature has not found a clear effect of age-of-marriage laws on the practice of child marriage. To analyze the possible reasons for the mixed results, we combine a document and discourse analysis of 88 age-of-marriage laws in 38 Sub-Saharan African countries with trend and regression analyses performed on 3312,019 individuals aged 15–49. We show that legal changes are not associated with a systematic decrease in child marriage even when accounting for the strictness of the law and specified punishments. The primary explanations center on the discrepancy between formal and informal institutions, and how national governments and individuals behaviorally accommodate this mismatch. The analysis highlights why treating child marriage laws as uniform interventions is prone to error and demonstrates that accounting for informal institutions matters. Adapting too much to informal norms may result in limited change, while completely overrunning informal institutions may create a significant gap between formal and informal rules, equally leading to limited progress. The findings also suggest that mandatory marriage registration could help address enforcement gaps.