How are election results certified, and what does a recount change?

A result becomes official in steps: the votes are counted, the count is checked and compiled, and then an official declares or certifies it. A recount is one possible check. It is a repeat tabulation of the votes cast, used to determine the correctness of an initial count, and it often takes place if the first tally is extremely close.

Who certifies depends on the place. In the United Kingdom, the returning officer is responsible for declaring the result. In Brazil, the Electoral Justice is responsible for the formal certification of the outcome. In the United States, compiling returns and validating the outcome that forms the basis of the official results is called canvassing, and state rules decide who signs off. Under a 2022 law, for presidential electors the governor submits the certificates of ascertainment unless state laws say otherwise. In four state elections since 2020, county officials withheld certification citing mistrust in voting machines or ballot errors, but certification proceeded after state interventions.

Recounts can change tallies, because errors can be found or introduced by people, such as transcription errors, or by machines, such as misreads of paper ballots. A machine recount is a retabulation of ballots, while a manual recount has each physical ballot reviewed for voter intent by one or more people. But they rarely reverse an outcome. In the US, of 4,687 statewide general elections between 2000 and 2015, 27 were followed by a recount and only three changed the outcome. In Canada, outcomes changed in four of 50 judicial recounts across twelve federal elections.

Recounts also have limits. In Canada, a recount deals solely with tabulation and counting, and judges decide whether ballots are valid and whether the count was accurate, not wider irregularities. Some places trigger them automatically, like Canada's 0.1% rule for federal elections. Others leave them optional, paid for by the candidate or party, or sometimes any interested voter.