Results & measures · Presidential election results
Swing
The change in margin between two elections — which way, and how far, a place moved.
Swing is the difference between a place's margin in one election and its margin in an earlier one, in percentage points. A county that voted D+10 in 2020 and D+4 in 2024 swung six points toward Republicans even though Democrats carried it both times. On pumsdata a positive swing is movement toward Democrats and a negative swing is movement toward Republicans.
Swing is often more revealing than the margin itself because it shows direction of travel: a deep-red county drifting eight points toward Democrats over two cycles is news even if it remains far from flipping — and the reverse is equally true.
Also known as: shift, trend.
Data: MIT Election Data & Science Lab, Harvard Dataverse.
See swing on the map
Explore presidential election results by state (1976–2024) and county (2000–2024) — margins, swings, and vote shares, election by election. Free while we're in beta.
Swing — FAQ
What is swing in election results data?+
The change in margin between two elections — which way, and how far, a place moved. Swing is the difference between a place's margin in one election and its margin in an earlier one, in percentage points. A county that voted D+10 in 2020 and D+4 in 2024 swung six points toward Republicans even though Democrats carried it both times. On pumsdata a positive swing is movement toward Democrats and a negative swing is movement toward Republicans.
Why does swing matter?+
Swing is often more revealing than the margin itself because it shows direction of travel: a deep-red county drifting eight points toward Democrats over two cycles is news even if it remains far from flipping — and the reverse is equally true.
Where does this election data come from?+
All figures come from the MIT Election Data and Science Lab (MEDSL), published on the Harvard Dataverse — state-level presidential returns 1976–2024 and county-level returns 2000–2024. pumsdata is an independent product that makes the data easy to map and compare, and is not affiliated with MEDSL or Harvard.