  This study analyzes political interactions in the European Parliament (EP) by
considering how the political agenda of the plenary sessions has evolved over
time and the manner in which Members of the European Parliament (MEPs) have
reacted to external and internal stimuli when making Parliamentary speeches. It
does so by considering the context in which speeches are made, and the content
of those speeches. To detect latent themes in legislative speeches over time,
speech content is analyzed using a new dynamic topic modeling method, based on
two layers of matrix factorization. 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 the political agenda of the EP has evolved
significantly over time, is impacted upon by the committee structure of the
Parliament, and reacts to exogenous events such as EU Treaty referenda and the
emergence of the Euro-crisis have a significant impact on what is being
discussed in Parliament.
