What triggers a recount and how it works.

With several high-profile races appearing to head for a recount in Florida, here’s how the process works and what to expect.

Secretary of State Ken Detzner, a Scott appointee overseeing elections, will call for a recount once the counties reach a deadline of Saturday at noon to submit unofficial results. If the margins remain under the 0.5 percent threshold, recounts must be ordered under state law.

Before then, election canvassing boards in each county will review provisional ballots to determine if they are valid. Provisional ballots are given to voters who don’t have proper ID or whose names don’t show up on the rolls at the precinct.

The canvassing boards, which typically consist of the supervisor of elections, a county judge and a county commission member, review the ballots to see if the signature matches the one on file when the voter first registered, and to determine if the voter didn’t already vote.

How close does a race have to be for an automatic recount?

According to the Florida Division of Elections, a machine recount is conducted if the winning margin based on the unofficial vote tally is within half a percentage point — 0.5 percent — of the total votes cast. In a machine recount, the ballots are simply fed back into the machines to see if they reach a different result, which tries to account for improperly calibrated machines and human errors in feeding ballots into the machines.

What leads to a hand recount?

A manual recount, where ballots with “overvotes” or “undervotes” are examined by hand, is called for if the race is even tighter. If, after a machine recount, the winning margin is equal to or less than one-fourth of one percent — 0.25 percent — of the total votes, a hand recount is done. These are the ballots where the voter’s intent is not clear.

Overvotes and undervotes are the two main categories that a hand recount could examine.

Overvotes are those in which the machines read more than one vote for a race on the same ballot. In the case of the Scott/Nelson race, it would mean a ballot had votes for both Scott and Nelson. A hand recount can sometimes show that one vote or the other was an unintentional marking or was crossed out.

Undervotes are those in which the machine reads no vote at all in a race.

When does a recount begin?

A recount can be called only after all of the unofficial results are in, and those results show a difference of less than 0.5 percent.

The unofficial results have to be in by noon on the fourth day after the election — this Saturday.

Afterward, if a machine recount is called for, it has to be done by 3 p.m. nine days after the election, which in this case is Nov. 15.

If those results show a race within 0.25 percent, the Florida Secretary of State will call for a manual recount.

Didn’t some of these candidates already concede?

Just announcing that you’re conceding the race isn’t enough to stop the mandatory recount. Losing candidates can stop it, but they’re required to alert the state Division of Elections in writing that they don’t want recount. No candidate has done so. The official, certified results are what counts.

What about provisional ballots?

Provisional ballots are those where the voter’s eligibility is in question — because the person lacked identification at the polls, for example. These voters were given until 5 p.m. Thursday to clear up the issue so the ballot can be counted. In an extremely close race, those ballots also could make a difference.

The canvassing boards, which typically consist of the supervisor of elections, a county judge and a county commission member, review the ballots to see if the signature matches the one on file when the voter first registered, and to determine if the voter didn’t already vote.

This sounds like important work. Can I watch?

Machine and manual recounts are open to the public.

How long might we wait for official results?

For this general election, returns from the counties are due at noon Nov. 18. The state will certify official results by Nov. 20.

These dates and deadlines, though, are subject to change if there are lawsuits, and the courts issue injunctions that delay the process.