US 2024 -> Models -> Retrospective

Fair’s presidential vote equation

Four key assumptions:

  • Incumbents have an advantage.
  • Voters favor change after two consecutive terms.
  • A slight bias favors the Republican Party.
  • The economy influences incumbent party votes.

Pure fundamentals

Yale economist Ray Fair is one of the pioneers of modern-day election forecasting (Fair, 1978). His presidential vote equation, which was first used to predict the 1980 election, is still applied today, although, not surprisingly, it underwent several revisions over the more than 40 years since its first publication.

Notably, the model takes a purely retrospective approach, exclusively relying on structural fundamental data and abstaining from the incorporation of any polling data.

The model

The presidential vote equation predicts the Democratic two-party popular vote. In its latest specification, it is formulated as (Fair, 2009; 2018):

V = 48.06 + 0.673 (G*I) – 0.721 (P*I) + 0.792 (Z*I) + 2.25 (DPER) – 3.76 (DUR) + 0.21 (I) + 3.25 (WAR)

Historical accuracy

The model, and earlier version thereof, has made forecasts for U.S. presidential elections since 1980. The table shows all forecasts that could be found.