A study reveals that implementing a gender quota in a democratic political system is only effective if it is high enough to convince the best qualified women to compete. A share of less than 25% may be ineffective in capturing the interest of potential female candidates.

José Tavares, professor at Nova SBE, together with Paulo Júlio, a former PhD student at Nova SBE, published the paper "The good, the bad and the different: Can gender quotas raise the quality of politicians?" in Economica journal which characterize the effects of a political gender quota in a citizen-candidate model. 

You can hear the full program here:

http://www.90segundosdeciencia.pt/episodes/ep-165-jose-tavares/