A key goal of primary reform is to improve the representativeness of our elections. While often conceived of in ideological terms, representativeness also demands that the candidate pool—and eventual winners—mirror the population being represented. As such, women’s competitiveness and representation are critically important when assessing the impact of reform to primary elections.
This report analyzes data on women’s competitiveness in congressional and state legislative elections from 2018–2024 and compares women’s performance under different primary rules. Overall, women appeared to make modest gains under all-candidate primaries compared to party primaries, particularly Republican women and women in state legislative races. Key findings include:
All-candidate primaries led to slightly higher rates of female candidate entry, and women made up a larger share of the candidate pool in state legislative elections.
- More women run in all-candidate primaries at both the congressional and state legislative level. In congressional races across the country, 56% of party primaries featured no female candidates, while only 27% of all-candidate primaries did. Likewise, in state legislative elections, there were no women in 64% of party primaries but just 43% of all-candidate primaries.
- In state legislative elections, the share of women in the candidate pool was two points higher in all-candidate primaries (31%) than party primaries (29%)—a result that was small but statistically significant. The opposite held true for congressional races, where women represented 24% of candidates in all-candidate primaries but 26% in party primaries (this result fell short of statistical significance).
For both congressional and state legislative elections, women nominated via all-candidate primaries were more likely to win general elections than those nominated in party primaries, and their margins of victory increased.
- There was a nine-point boost for congressional elections and a four-point jump for state legislative races—both differences were statistically significant.
- Female incumbents’ margins of victory increased under all-candidate primaries compared to party primaries—and these results were statistically robust when compared to the change for male incumbents.
There are important nuances for women’s competitiveness depending on race dynamics, party, and primary type:
- The presence of male incumbents remained a barrier to women’s competitiveness across both primary rules.
- Republican women appeared to gain the most from primary reform, as they were more likely to run, advance from primaries, and win general elections under all-candidate primaries than party primaries. Democratic women performed equally well under both primary rules.
- Partially opening the party primary via open and semi-open primaries did not result in considerable changes in women’s competitiveness or representation. However, it’s encouraging that women’s competitiveness does not appear to be harmed by incremental open-ness.
A potential limitation of this research is the relatively short timespan for which data was available (2018–24), especially since this period witnessed a significant increase in the number of women elected to office. Furthermore, that only five states used all-candidate primaries also makes it challenging to generalize regarding the impact of primary reform. Future research should build upon this research by examining a larger time series and using additional methods to assess the robustness of the findings.
