How do election recounts actually work?

Recount rules are set entirely by state law and vary considerably. Some states order an automatic recount when the margin falls within a specified percentage, commonly a fraction of one percent. Others require a candidate or voter to request one, sometimes with a deposit or full payment of costs that is refunded only if the outcome changes. Deadlines are short and procedures differ on whether ballots are recounted by machine, by hand, or by a combination, and on which ballots including provisional and mail ballots are subject to review.

The empirical record is clear on how much they matter. Analyses of statewide recounts over recent decades find that they shift margins by very small amounts, typically in the hundreds of votes out of millions cast, and that reversals occur only when the initial margin was extraordinarily thin. The most cited example, the 2008 Minnesota Senate race, was decided by a few hundred votes after a lengthy recount and litigation. A recount in a race decided by tens of thousands of votes has never overturned a result and is not a realistic mechanism for doing so.

Two related processes are frequently confused with recounts. Canvassing is the routine post-election verification and certification of results that occurs in every election and legitimately changes reported totals as outstanding mail and provisional ballots are counted, which is why election night numbers are unofficial. Risk-limiting audits are statistical checks in which a random sample of paper ballots is hand-counted and compared against machine results, escalating to a fuller count if discrepancies appear, and they have been adopted in a growing number of states as a more efficient verification tool than a full recount. Both depend on a voter-verifiable paper record, which is the reason election security experts have pushed states toward paper-based systems.