Why Standard Measures Miss UK MPs' Ideology
Measuring left–right ideology of UK MPs is difficult because party discipline and strategic opposition voting limit variation in roll-call behavior. Conor Gaughan addresses this measurement gap by using MPs' social media followership to recover ideological positions that are otherwise obscured in parliamentary votes.
How Social Media Followership Was Turned Into Ideal Points
Gaughan assembled Twitter (X) follower networks for 591 MPs sitting in the House of Commons as of 22/08/2022 and applied correspondence analysis (CA) to those bipartite networks. CA maps patterns of co-following into latent dimensions; here the primary dimension is interpreted as a left–right ideological scale that locates MPs according to who follows them online.
Validation Against Expert Judgments
The social-media-derived scores are validated against an expert survey. Validation results show very strong between-party separation (R2 = 0.93) and substantial within-party agreement with experts (Conservatives: r = 0.84; Labour: r = 0.81), indicating the CA-based estimates capture both party differences and meaningful intra-party variation.
A Real-World Test: Predicting the September 2022 Conservative Endorsements
To demonstrate substantive utility, the paper uses the ideal-point estimates to predict which MPs endorsed which candidate in the September 2022 Conservative leadership contest. An MP's estimated position on the CA-based left–right scale was a statistically significant predictor of endorsement choice; notably, Liz Truss drew support primarily from MPs placed further to the right on the estimated scale.
What This Means for Research on UK Politics
This research note offers a replicable, data-driven method for estimating MP ideology in settings where roll-call data are uninformative. The approach provides a practical tool for studying intraparty variation and strategic behavior, while its usefulness will depend on the scope and representativeness of social-media followership as a proxy for political alignment.
| Estimating Ideal Points of British MPs Through Their Social Media Followership was authored by Conor Gaughan. It was published by Cambridge in BJPS in 2024. |
