Gender Bias in Party Gatekeeping: Evidence from Polish Parliamentary Elections, 2005–2023

Gender quota laws are widely adopted to increase women's legislative representation, yet their effects depend critically on design and enforcement. This paper examines Poland's 2011 candidate quota law, which mandates 35% female candidates but imposes no placement requirements, through two empirical studies drawing on electoral commission, parliamentary activity, and biographical data for all MPs and candidates between 2005 and 2023. Study 1 finds that women MPs are consistently better educated than men and score significantly higher on a composite measure of parliamentary activity. Both findings are consistent with a positive selection mechanism: higher structural barriers to entry produce a cohort of women who, conditional on winning a seat, outperform their male peers on observable dimensions of quality. Study 2 examines whether the quota changed how parties allocate women across candidate lists. Before 2011, there was no detectable gender gap in access to winnable list positions. After 2011, a large and stable penalty emerged for female challengers that has not diminished across four consecutive post-quota elections. Female incumbents face significantly better placement odds than male incumbents, and voter-level analysis indicates that voters do not drive this disadvantage. Together, the findings suggest that Poland's quota expanded formal numerical inclusion while leaving party gatekeeping largely intact.