Institutional Quality and Income Inequality: A Meta-Analysis and Meta-Regression Analysis

Income inequality continues to exhibit substantial variation across empirical studies examining the role of institutional quality, with findings that remain inconsistent and inconclusive. This study addresses this inconsistency by conducting a meta-analysis and meta-regression of the relationship between institutional quality and income inequality, based on 19 Scopus-indexed studies published between 2015 and 2025. The meta-analysis results indicate that, on average, institutional quality is negatively but insignificantly associated with income inequality, accompanied by substantial heterogeneity across studies. Subgroup analysis by institutional dimensions reveals that among the World Governance Indicators, only rule of law exhibits a negative and statistically significant effect on income inequality, while other dimensions show inconsistent and non-robust effects. Meta-regression analysis further demonstrates that the interaction between institutional quality and data period explains the largest share of heterogeneity, highlighting the importance of temporal horizons. In particular, the inequality-reducing effect of rule of law emerges consistently in long-term studies but not in short-term analyses, suggesting that institutional mechanisms such as contract enforcement and property rights protection require time to translate into distributive outcomes.