Identifying Brexit voting patterns in the British house of commons: an analysis based on Bayesian mixture models with flexible concomitant covariate effects

The results of some divisions related to Brexit held in the House of Commons are investigated. In particular, a new class of mixture models with concomitant covariates is developed to identify groups of members of parliament with similar voting behaviour. The methodological novelty lies in the flexibility introduced by the use of smooth functions to model the effect of concomitant covariates on the component weights of the mixture. Results show this approach allows to quantify the effect of the age of members of parliament, as well as preferences and competitiveness in the constituencies they represent, on their position towards Brexit.