Open seat
Definition
An open seat is a race where no incumbent is running, either because none filed or the incumbent withdrew before the ballot was set. Without an incumbent, the seat is guaranteed to go to a newcomer.
Why it matters
Open seats draw more candidates and more competitive spending than races with an incumbent, since neither side already holds a name-recognition or fundraising edge. Ballotpedia tracks open-seat counts each cycle as a proxy for how competitive an election year actually is, because incumbency is usually the single biggest predictor of who wins.
Seen in the wild
Ballotpedia's 2024 state legislative election analysis identified open seats nationwide where no incumbent filed, noting they draw disproportionately more candidates per seat than races with an incumbent on the ballot.1