From Seats to Power: How Personal Networks Shape Women’s Access to Political Leadership

Over the past few decades, the proportion of women in national parliaments has grown significantly worldwide, moving from a global average of 11% in 1995 to over 27% today. Despite this progress in parliamentary representation, a persistent gender gap remains in access to top political leadership roles. This phenomenon suggests that the path from a parliamentary seat to a position of substantive power is not the same for men and women. While existing research has extensively analyzed macro-level institutional rules (e.g., gender quotas) and micro-level voter biases, these factors are insufficient to explain why the "glass ceiling" persists even in contexts where formal barriers have been lowered and electoral penalties are minimal. This study argues that a crucial, yet under-examined, mechanism for this inequality lies at the meso-level. We claim that the "glass ceiling" is a dynamic process reproduced by the collaboration networks through which all legislative work is accomplished. Our framework is grounded in social capital theory and hypothesizes two distinct mechanisms. First, the Structural Disadvantage Hypothesis, suggesting that women are relegated to peripheral network positions due to homosocial patterns of collaboration that favor the integration of male colleagues. Second, the Differential Returns Hypothesis, positing that even when women achieve central positions, they are unable to convert this social capital into legislative success at the same rate as men. To test these hypotheses, this study leverages an unprecedented longitudinal dataset covering the entire legislative history of the Italian Republic. The Italian case provides an ideal "laboratory" for this analysis due to its long and stable parliamentary tradition and the significant variation in the proportion of female MPs over time. The dataset was constructed by collecting information on every legislative proposal, along with its full list of sponsors and co-sponsors, from the official Open Data portals of both parliamentary chambers. The final dataset spans 18 legislative terms, from 1948 to 2022, encompassing tens of thousands of bills and hundreds of thousands of sponsorship ties. This extensive and granular data allows for the construction of dynamic co-sponsorship networks for each legislature, capturing the evolution of collaborative ties over time with high precision. Methodologically, this paper advances beyond traditional static network analyses. We employ a dynamic approach, constructing a panel dataset that tracks legislators' network positions and their legislative effectiveness at multiple points within each term. This design allows us to isolate the effect of network metrics on the probability of passing legislation. The study’s primary contribution lies in its test of a powerful "differential returns" mechanism. Our central expectation is that while a central network position enhances legislative success for all politicians, this effect will be substantially weaker for women. Confirming this would demonstrate that the barrier is shaped not only by access to influential networks but also by the unequal rewards derived from them. By operationalizing and testing how women’s social capital is devalued, this study aims to advance a new meso-level explanation for persistent gender inequality in parliamentary career advancement.