It Took Two Weeks to Call Every State in 2020. This Is When to Expect Results This Year.

While Tuesday’s election will not follow the exact same patterns, some of the same factors could extend the release of results until later into the week. That means we may again have to wait until after Election Day to know the outcome in some of the most competitive states. Here’s how vote reporting unfolded in 2020:

The longer wait for results in 2020 contributed to false claims that the election had been stolen from President Trump. In reality, the counting of an unprecedented volume of mail ballots in conjunction with very close races meant that it took longer than usual to project winners.

There are a few reasons why Tuesday’s election will differ from the one in 2020. It’s a midterm year, which generally produces lower voter turnout than a presidential election. In part because of the lifted Covid restrictions, many states expect a smaller share of ballots cast by mail, which often take longer to count than those cast in person and sometimes are allowed to arrive days after the election. Also, it’s difficult to predict which races will be decided by the final ballots.

Still, some factors remain the same. Republican-led legislatures in Michigan, Pennsylvania and Wisconsin have resisted entreaties from local election officials to allow mail ballots to be processed earlier. And extremely close races can trigger automatic recounts or runoff elections. If control of the Senate comes down to the race in Georgia, for example, we may not know the outcome until a Dec. 6 runoff.

The Times relies primarily on a team of analysts and researchers at The Associated Press to make race calls, which happens when a trailing candidate no longer has a path to victory. Sometimes winners are projected in races in which only a small share of votes have been reported. These early calls can be made if the race is not closely contested, or if the party or candidate has a history of consistent wins in the county or state. The calls could also be based on results from a pre-election survey.

The Times asked officials in every state and Washington, D.C., about their expectations for this year and what, if any, rules have changed since 2020 that could affect vote counting and reporting. Many noted that vote counts are not official until they are certified in each state.