Journal of Experimental Political Science
How Durable Are Experimental Increases in Women’s Representation?
2026-07-06
Do field experimental interventions produce durable changes in gender representation? We examine the persistence of experimental treatment effects in Karpowitz, Monson, and Preece (2017), where a single letter from Republican Party leaders significantly increased women’s election to state delegate positions. Two years later, differences between treatment and control conditions evaporated. Treated precincts largely retained earlier experimental gains, but the treatment effect size was smaller because of increases in the control condition. We examine four possible explanations for this pattern. First, we find considerable evidence of an incumbency effect among women in one treatment condition. Second, increases in women’s representation in the control condition appear to be related in part to larger turnout during the 2016 election cycle. Finally, we find little evidence of lasting attitude changes about women’s representation and few traces of post-experimental spillover.