Structure and evolution of a European Parliament via a network and correlation analysis

TL;DR

This study analyzes the structure and evolution of the Finnish parliament's network over 16 years using correlation and community detection methods, revealing insights into political dynamics and individual roles.

Contribution

It introduces a network-based methodology to quantitatively analyze parliamentary relationships and their evolution, linking structural features to political attributes.

Findings

Identification of community structures aligned with political attributes

Detection of temporal changes in inter-party correlations

Insights into individual roles as proponents or signers

Abstract

We present a study of the network of relationships among elected members of the Finnish parliament, based on a quantitative analysis of initiative co-signatures, and its evolution over 16 years. To understand the structure of the parliament, we constructed a statistically validated network of members, based on the similarity between the patterns of initiatives they signed. We looked for communities within the network and characterized them in terms of members' attributes, such as electoral district and party. To gain insight on the nested structure of communities, we constructed a hierarchical tree of members from the correlation matrix. Afterwards, we studied parliament dynamics yearly, with a focus on correlations within and between parties, by also distinguishing between government and opposition. Finally, we investigated the role played by specific individuals, at a local level. In particular, whether they act as proponents who gather consensus, or as signers. Our results provide a quantitative background to current theories in political science. From a methodological point of view, our network approach has proven able to highlight both local and global features of a complex social system.