A complex network approach to political analysis: application to the Brazilian Chamber of Deputies

TL;DR

This paper introduces a network-based method to analyze political dynamics using voting data from the Brazilian Chamber of Deputies, revealing limited ideological diversity and coalition patterns over time.

Contribution

The study applies a novel network approach to political analysis, uncovering coalition structures and early signs of party isolation in a multi-party system.

Findings

Effective number of communities is about 3, indicating limited ideological diversity.

Identified patterns of coalitions between different parties.

Detected signs of early party isolation before impeachment proceedings.

Abstract

In this paper, we introduce a network-based methodology to study how clusters represented by political entities evolve over time. We constructed networks of voting data from the Brazilian Chamber of Deputies, where deputies are nodes and edges are represented by voting similarity among deputies. The Brazilian Chamber of deputies is characterized by a multi-party political system. Thus, we would expect a broad spectrum of ideas to be represented. Our results, however, revealed that plurality of ideas is not present at all: the effective number of communities representing ideas based on agreement/disagreement in propositions is about 3 over the entire studied time span. The obtained results also revealed different patterns of coalitions between distinct parties. Finally, we also found signs of early party isolation before presidential impeachment proceedings effectively started. We believe that the proposed framework could be used to complement the study of political dynamics and even applied in similar social networks where individuals are organized in a complex manner.