Research on the impact of gender quotas in open-list proportional representation systems has described quotas as ineffective or even paradoxical. While some authors argue that gender quotas without a placement mandate will be essentially ineffective since most women will be nominated to unpromising positions, others suppose that women will be disadvantaged by gender quotas because the increase in the number of female candidates will decrease the average number of preferential votes cast for women. We reexamine the evidence for these claims by analyzing the case of Poland. We demonstrate that the gender quota introduced there in 2011 increased the number of women placed at promising ballot positions and had very little impact on the number of preferential votes cast for women. Additionally, using simulations, we show that the quota had a positive impact on the number of elected women.