Women and Power: Unpopular, Unwilling, or Held Back?

Quotas that force political parties to increase the number of female candidates have a neutral or beneficial effect on the parties' electability.


There is a persistent gender gap in politics. Some researchers have attributed this to supply-side factors, focusing on women’s unwillingness or reluctance to run for office when faced with personal challenges or the competitive nature of politics, or when given the option of volunteering as group representatives without running in an election. Alternatively, some research has attributed the gender gap in politics to demand-side factors, examining whether voters have an aversion to female politicians, which disincentivizes political party leaders from increasing the number of women candidates.

In this study, researchers examined claims about the demand-side factors—whether having female candidates hurts political parties’ electability—by using the case of Spain’s 2007 Equality Law. This law mandated a 40 percent minimum female quota on electoral ballot lists in towns with populations above 5,000 people, increasing the number of women candidates by 27 percent. This study measured party success in election outcomes, comparing data in municipalities both before and after the Equality Law was enacted.


Quotas that forced political parties to increase the number of female candidates had a neutral or beneficial effect on the parties’ electability.

  • The political parties forced by the quota to accept more female candidates experienced electoral outcomes that were slightly more positive than or equal to parties not affected by the quota.
  • Parties forced to accept a larger share of female candidates (relative to the other political parties within their municipality) experienced greater improvement in their electoral outcomes. Specifically, parties forced to increase the number of female candidates by 10% more than their opponents experienced a 4.2% gain in votes.
  • Voter turnout in municipalities affected by the quota did not decrease as a result of the increase in the number of female candidates. Therefore, voters did not appear to have substantial aversion to female candidates.

Increasing the number of female candidates was a feasible and profitable strategy for most political parties affected by the 2007 Spanish Equity Law. However, these affected parties did not meet the 40% minimum threshold of female candidates until they were forced by the government mandate. Therefore, researchers interpret this historical case to show that the barrier to women entering politics may not be due to either supply or demand-side factors, because there was a ready supply of female politicians to join the municipal ballots and voters were eager to vote for them as evidenced by voter turnout. Instead, the findings in this study suggest that the barrier to gender equity in political representation may be the internal party dynamics that prevented women who were willing to run for office and who were popular among voters from being placed on ballots.


In this study, researchers investigated the impact of gender quotas from the 2007 Spanish Equity Law by comparing political parties’ voting outcomes in municipalities affected by the law with voting outcomes in municipalities unaffected by the law. The municipalities measured in this study were limited to those with populations between 5,000 and 10,000 people. 

To assess overall voting trends regarding attitudes towards female politicians, the study compared voting outcomes from 2003 (prior to the implementation of the Spanish Equity Law) with those from 2007. Researchers also tested the data to see whether unemployment rates in different regions impacted the effectiveness of the law, and found that unemployment rates had no effect.

The gender of candidates from municipal ballots in 2003 was assessed based on the first name of the candidate (which is rarely gender-ambiguous in Spanish). The gender of the 2007 candidates was known, in addition to information about the number of votes for all ballots, the estimated municipal populations at the time of election, and the number of registered voters in each town. Because the law only applied to municipalities exceeding the 5,000-person threshold, meaningful data could only be assessed for 4,582 municipalities in 2003 (before the introduction of the quota) and 144 quota municipalities and 1,354 non-quota municipalities in 2007 (after the introduction of the quota).

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