Legislative Effectiveness and Informal Institutions: Evidence from Latin America
Tuesday, January 6, 2026
In fragmented presidential systems, there is discussion about why some legislators are more effective than others. In an article published in Latin American Politics and Society, Beatriz Rey examines Brazil’s highly fractionalized party system to understand how lawmakers advance legislation when parties fail to provide sufficient coordination. The study argues that legislative member organizations (LMOs) supply policy expertise and political information that parties often lack, enabling legislators to sponsor and shepherd bills more effectively. Rey tests this argument using a modified version of the Legislative Effectiveness Scores (LES) – based on those produced by the Center for Effective Lawmaking (CEL) – for both bill sponsors and rapporteurs in Brazil’s Chamber of Deputies. Quantitative results show that affiliation with highly structured LMOs is associated with greater legislative effectiveness, while weakly organized LMOs produce no measurable gains. Public security LMOs increase both sponsorship and rapporteurship effectiveness, while agribusiness LMOs primarily boost rapporteurship.
The analysis further shows that party affiliation continues to matter, but parties do not consistently provide the informational resources or coordination necessary for legislative success. Drawing on qualitative evidence, the study identifies two mechanisms through which strong LMOs operate: placing aligned members in key legislative positions and leveraging technical expertise to shape agendas and voting cues. These findings recast legislative effectiveness in Brazil as a function of cross-party informational networks rather than parties alone. More broadly, the article identifies clear scope conditions under which LMOs can enhance lawmaking in other multiparty presidential democracies.
This article was sponsored in part by the CEL as part of our small grants program.
To learn more, read the full report here.
Photo: “Brazilian National Congress” by * Luis Felipe Luz * is licensed under CC BY 2.0.
