Results & measures · Presidential election results
Margin of victory
The gap between the parties in percentage points — Democratic share minus Republican share.
The margin of victory is the gap between the two major parties, measured in percentage points of all votes cast. On pumsdata it is stored as a signed number — the Democratic share minus the Republican share — so +12.4 means the Democrat carried the place by 12.4 points (shown as D+12.4) and −3.5 means the Republican carried it by 3.5 points (R+3.5).
Margins are the standard shorthand for how contested a place is: a margin inside roughly five points usually reads as competitive, while D+40 or R+40 territory is a landslide. Because the margin is computed over all votes — including third-party and write-in votes — the two parties' shares don't have to add to 100.
Also known as: margin, point margin, D+, R+.
Data: MIT Election Data & Science Lab, Harvard Dataverse.
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Margin of victory — FAQ
What is margin of victory in election results data?+
The gap between the parties in percentage points — Democratic share minus Republican share. The margin of victory is the gap between the two major parties, measured in percentage points of all votes cast. On pumsdata it is stored as a signed number — the Democratic share minus the Republican share — so +12.4 means the Democrat carried the place by 12.4 points (shown as D+12.4) and −3.5 means the Republican carried it by 3.5 points (R+3.5).
Why does margin of victory matter?+
Margins are the standard shorthand for how contested a place is: a margin inside roughly five points usually reads as competitive, while D+40 or R+40 territory is a landslide. Because the margin is computed over all votes — including third-party and write-in votes — the two parties' shares don't have to add to 100.
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.