First wife advantage: seniority rank and intra-household consumption inequality in polygynous households in Burkina Faso

Understanding intra-household resource allocation is critical for welfare analysis, yet consumption inequality within subgroups – particularly among co-wives – remains underexplored due to methodological and data constraints. This study introduces a novel empirical approach, to estimate individual resource shares for co-wives in polygynous households under flexible assumptions, using data from Burkina Faso. Our findings are threefold. First, consistent with prior literature, husbands receive a disproportionately large share of household resources in both monogamous and polygynous households, with inequality being more pronounced in the latter. Second, senior wives receive significantly larger resource shares than junior wives; while biological children modestly improve a junior wife's relative position, seniority rank is the dominant and structurally embedded driver of resource allocation. Third, poverty analysis reveals that women – especially junior wives – and children are the most materially deprived. These results demonstrate that targeted poverty policies must account for intra-household hierarchies, particularly within polygynous families.