undervotes

An undervote is a ballot in which no selection is recorded for a given contest. Undervotes can occur on any ballot type and may reflect voter intent (a deliberate choice not to vote in that contest) or confusion or error. They are distinct from overvotes, where a voter selects more than one option for a single-seat contest. An undervote does not render a ballot invalid; it remains a cast ballot, but no candidates receive a vote in that contest.

Measurement and scope: Election officials calculate undervotes as the number or percentage of ballots in a contest that have blanks for that contest. In multi-seat races, leaving some seats unfilled can also produce undervotes for the unfilled seats, even if other marks are made elsewhere on the ballot. Undervotes can occur in paper ballots, ballot marking devices, and electronic voting systems.

Causes and effects: Causes include ballot design that obscures choices, lengthy or confusing instructions, accessibility barriers, voter fatigue, or simple indiscipline. The effect of undervotes varies with the margin of victory; in close races, a high undervote rate can influence outcomes. Analysts often report undervote rates to assess ballot design and voter behavior. For turnout statistics, undervotes are counted as ballots cast but not recorded for the candidate or option in question.

Response and improvement: Remedies include clearer instructions, more intuitive ballot layouts, better accessibility features, and voter education. Some jurisdictions use ballot marking devices to help voters navigate contests. Post-election audits and ballot-level analyses may examine undervote patterns to inform future ballot design and election administration.