A fresh statistical approach for multiparty electoral data promises to transform comparative politics research.

Data & Methods:

* Analyzes district-level elections across the UK, moving beyond traditional two-party tools like regression analysis.

* Addresses previously biased measures of incumbency advantage.

Key Findings:

• Incumbency does offer a slight edge but it is small and stable across parties.

• Contrary to claims of growing advantages, our model shows no such trend over time.

• The benefit varies significantly depending on the party holding the seat.

Why It Matters:

This methodology provides crucial insights for understanding British electoral dynamics. We show how to estimate each party's inherent incumbency advantage and demonstrate that these partisan effects explain much of what appears as a cross-party trend in previous biased measurements.