The Effect of Gender Quotas on Women's Representation in National Parliaments

This study examines the causal relationship between the adoption of gender quotas and the increase in the share of women in national parliaments. While some research points to a significant effect of gender quota introduction on women's parliamentary representation, other studies indicate its heterogeneity depending on the type of electoral system and the mechanism of quota implementation. This paper uses data on more than 160 countries for the period 1997–2015, drawing on the Quota Adoption and Reform Over Time (QAROT) database and World Bank indicators. The effect is estimated using a quasi-experimental design based on a stacked-cohort regression by year of quota adoption. This approach allows the effect of quota introduction to be separated from general socio-economic and political differences between countries and from the global trend. The results show that quota introduction is significantly associated with a 7–9 percentage point increase in the share of women in parliament within 12 years after the reform. No differences in the pre-reform dynamics of women's parliamentary representation were found, which supports the validity of the design and the reliability of the results obtained.