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.

本研究使用基于两层非负矩阵分解（NMF）的新动态主题建模方法分析了欧洲议会（EP）大会的政治议程及议员的讲话反应，结果显示两层NMF是现有动态主题建模方法的有力替代，并可揭示不受现有方法捕捉的专业主题和相关词汇。政治议程在欧洲议会显著演变并受到外部事件的影响，而MEP对议程的贡献也受到投票行为和议会委员会结构的影响。

运用动态主题建模探索欧洲议会的政治议程