Exploring the Political Agenda of the European Parliament Using a Dynamic Topic Modeling Approach

TL;DR

This paper introduces a new dynamic topic modeling method based on two-layer NMF to analyze the evolution of the European Parliament's political agenda through legislative speeches from 1999 to 2014, revealing how external events and internal structures influence MEPs' speeches.

Contribution

The study presents a novel two-layer NMF approach for dynamic topic modeling, effectively capturing niche topics and their vocabularies in legislative speech analysis.

Findings

EP's political agenda evolves significantly over time.

External events like EU referenda influence agenda shifts.

Voting behavior and committee structures impact MEP speech content.

Abstract

This study analyzes the political agenda of the European Parliament (EP) plenary, how it has evolved over time, and the manner in which Members of the European Parliament (MEPs) have reacted to external and internal stimuli when making plenary speeches. To unveil the plenary agenda and detect latent themes in legislative speeches over time, MEP speech content is analyzed using a new dynamic topic modeling method based on two layers of Non-negative Matrix Factorization (NMF). This method is applied to a new corpus of all English language legislative speeches in the EP plenary from the period 1999-2014. Our findings suggest that two-layer NMF is a valuable alternative to existing dynamic topic modeling approaches found in the literature, and can unveil niche topics and associated vocabularies not captured by existing methods. Substantively, our findings suggest that the political agenda of the EP evolves significantly over time and reacts to exogenous events such as EU Treaty referenda and the emergence of the Euro-crisis. MEP contributions to the plenary agenda are also found to be impacted upon by voting behaviour and the committee structure of the Parliament.