Behind the Guardian’s analysis of 100 years of MPs’ language on immigration

Methodology: how we trained a machine learning model to analyse rhetoric on immigration in the UK parliament over the course of a century

The Guardian has revealed a significant rightward shift toward sentiment relating to immigration among MPs speaking in the House of Commons in the past five years.

To do this analysis the Guardian's Data Science and Data Projects teams, in collaboration with University College London, developed an in-house machine learning model to measure linguistic sentiment in debates in the Commons over the course of a century.

Unlike off-the-shelf sentiment models, the Guardian's version distinguishes sentiment directed specifically at immigration from general emotionally charged language about any topic.