# Electoral-cycle model

The electoral-cycle is a naive model, developed by Helmut Norpoth, which predicts the election outcome based on electoral history. In particular, it uses the vote of the two most recent elections as predictor variables in a linear model, which has been estimated based on data from all elections since 1828. The model’s vote equation reads as

V = 49.2 + 0.525 `Vt-1` – 0.474 `Vt-2`,

where V is the incumbent party’s popular two-party vote, `Vt-1` is the incumbent party’s popular two-party vote in the last election, and `Vt-2` is the incumbent party’s popular two-party vote in the second to last election.

The model reveals the following pattern:

• There is a boom-bust cycle of electoral fortunes
• The cycles are irregular in length (period) as well as width (amplitude)
• The average length of a cycle is estimated as 5.2 terms
• The White House party can expect to stay in office 2.6 terms

For 2016, the electoral-cycle model predicts the Democratic candidate to achieve 48.6% and the Republican candidate to achieve 51.4% of the popular two-party vote.

#### Reference

Norpoth, Helmut (2014). The electoral cycle. PS: Political Science & Politics, 47(2), 332-335.