Who speaks for whom? Gendered representation in interest group advocacy before parliament

Abstract This paper investigates the conditions under which women are more likely to represent interest groups in parliamentary hearings, shifting attention from the content of advocacy to the identity of advocates. While existing research has focused on how interest groups gain access to legislative venues, it has largely overlooked who delivers these messages and how messenger characteristics shape political representation. Drawing on theories of gender representation, interest group advocacy, and source effects, we develop a framework that distinguishes between structural and strategic representation and examine whether gender is deployed as a symbolic and relational resource in legislative settings. Using an original dataset covering all interest group appearances in the Spanish Parliament from 1996 to 2023, and hierarchical logistic regression models with Bayesian inference, we analyze how organizational, institutional, and contextual factors shape gendered representation. The findings show that citizen groups are significantly more likely than economic organizations to be represented by women, and that female representation increases with the proportion of women MPs on parliamentary committees. Gendered patterns also vary across policy domains and hearing characteristics. Importantly, the results provide evidence consistent with strategic adaptation: interest groups appear more likely to select female representatives in gender-diverse institutional environments, suggesting that gender functions as a form of strategic signaling rather than solely reflecting internal organizational structures. These findings contribute to research on interest groups and political representation by highlighting how identity operates as a political resource, with implications that extend beyond parliamentary lobbying to broader debates on descriptive and substantive representation.