America First Insight
State Partisan Baseline
AFI SPB
Description
The America First Insight State Partisan Baseline (SPB) is a rival to the Cook Political Report's Partisan Voting Index (PVI). The SPB provides a partisan baseline for each state, estimating election outcomes if both parties fielded candidates of similar quality in open seats with presidential-level turnout.
Using data from statewide races between 2016 and 2024, with the 2024 presidential election weighted most heavily, the SPB serves as a starting point for predicting neutral races and identifying underperforming or overperforming candidates.
Methodology
The AFI SPB is calculated using a weighted average of presidential, senatorial, gubernatorial, congressional generic ballot, and voter registration data (where applicable) from the past three election cycles. Sourced from public election records, the data is weighted by recency and type—presidential data carries the most weight, while generic House ballot data carries the least. Each state’s baseline reflectssuspend its consistent partisan tilt, expressed as a percentage lean toward Democratic or Republican candidates.