Predicting endorsement of leadership candidates in the September and October 2022 Conservative leadership elections using MP Twitter networks.

The tightly disciplined nature of the U.K parliamentary system typically constricts the voting behaviour of MPs, forcing them to vote as largely homogenous party blocs. This has consequently rendered traditional spatial voting methods for scaling their ideological positions sub-optimal. Fortunately, the widescale uptake of Twitter by U.K parliamentarians over the last decade has presented a unique opportunity to scale ideological position using Twitter networks. Currently, 91% of U.K MPs have an active Twitter account with a combined total of over 34 million followers. This paper employs contemporary multidimensional scaling methods to estimate the ideological positions of MPs in the House of Commons based on their Twitter follower networks. Validation against expert survey estimates confirm strong between and within-party model accuracy. These ideal point estimates are then used to predict endorsement for leadership candidates in the September and October 2022 Conservative party elections. Results indicate that MP ideology was a statistically significant predictor of candidate endorsement in both elections. These findings demonstrate the efficacy of using social media networks to predict offline political elite behaviour.