County election boards have begun processing the more than 2.5 million mail-in votes already cast in this year’s general election, but that early start doesn’t mean people should expect timely results come next week's election night.

Indeed, just the opposite will be true. Even if counties begin reporting mail-in ballot results as the polls close Nov. 3, public-opinion surveys have shown a partisan divide between voting by mail and voting in person on Election Day. Democrats are more likely to vote by mail and Republicans in person.

The Election Day votes this year in New Jersey will be paper provisional ballots that won’t even start being counted until Nov. 10, so there's a chance any initial returns will be skewed.

Enter your number to get our free mobile app

“Well, this is what I always say in every single election year, for voters to always be patient,” said Secretary of State Tahesha Way. “But of course, in this unprecedented time, it is certainly possible that the vote for various races may be known or may not be known on election night.”

County boards of canvassers have to meet by Nov. 20 to certify election results. Those results must be transmitted by the county clerks to the secretary of state by Nov. 23. The Board of State Canvassers will certify the results by Dec. 8, in advance of the Electoral College meeting on Dec. 14.

“While we are accustomed to seeing results on election night, in actuality election officials count every properly cast ballot, and then official results are certified, which can take days or even weeks in order in ensure the results truly reflect the will of the people,” Way said.

Election boards first remove certificates from the inner envelopes, which maintains a vote’s secrecy. Those stacks of envelopes can now be opened and the ballots fed into scanners that record the votes and kick out ones that raise questions that must be looked at by a person to resolve. Counties aren’t allowed to tabulate the count until Election Day, so nobody knows the partial results while the voting continues.

Counties were allowed to start counting ballots Saturday, under a state law enacted in late August allowing them to be processed starting 10 days before the election. One-third of counties began over the weekend, others will get started this week, and a few intend to wait.

The early vote received and recorded by counties through Sunday amounted to 40% of registered voters, including inactive voters who weren’t sent mail-in ballots. It exceeds 63% of New Jersey’s total participation in the 2016 presidential election.

“New Jersey is one of those states where voting by mail used to be pretty unusual, pretty low, and then now it’s up to like 60, 70% of people in New Jersey are likely to vote by mail,” said Katherine Ognyanova, an assistant professor of communication at Rutgers University in New Brunswick and co-author of a recent report about likely voting result patterns in this election.

“So, this will put some strain on the system,” Ognyanova said. “It is possible that the ballot counting is not going to be fast enough so that we know results by election night.”

In many states – including some of the battlegrounds that will dominate election night coverage being watched and read across the country – the pattern is expected to be the reverse of New Jersey’s, with President Donald Trump seeming to be ahead based on initial Election Day turnout results, only to see mail-in votes that favor former Vice President Joe Biden being counted and announced later.

Ognyanova said some states – like New Jersey – allow ballots received after Election Day to be counted. Others don’t allow mail-in votes to begin being counted until Election Day, which would have been the case in New Jersey this year except that the law was recently changed.

“And so what we think is likely to happen is that on election night, when mostly the in-person ballots are counted, we might see a lead for Donald Trump, where after all of the mail ballots get counted, we might see that Joe Biden is actually winning pretty solidly,” Ognyanova said.

“Our concern about that was that media handles this responsibly and makes sure that people have the correct expectations that results might change so that the legitimacy of the election is not questioned when we see this swing after the mail ballots get counted,” she said.

In New Jersey, some mail-in ballots will be received and counted after Election Day, so long as they arrive by 8 p.m. Thursday without a postmark or by 8 p.m. Tuesday, Nov. 10, with a postmark of Nov. 3 or earlier.

People who choose not to return their mail-in ballot will be able to vote at their polling place on Election Day, but only those with disabilities will vote on machines. Others will vote on provisional paper ballots that won’t be counted until Nov. 10, to ensure voters didn’t cast a second ballot through the mail.

Early-vote data compiled by the U.S. Elections Project show only a slight partisan gap in the share of people casting mail-in ballots: Nearly 50% of Democrats and 46% of Republicans, along with more than 30% of unaffiliated voters.

However, given the overwhelming Democratic tilt of voter registration in New Jersey, those percentages translate to a big advantage in terms of votes cast by registered Democrats – more than 1.18 million, compared with almost 631,000 Republicans. Of course, it’s not known how many registered partisans supported only their own party, or how the nearly 678,000 unaffiliated voters have voted.

Ognyanova and her fellow researchers are watching nine states where the presidential race is competitive, within 10 points: Texas, North Carolina, Alaska, Pennsylvania, New Hampshire, Ohio, Wisconsin, Michigan and Nevada. She said Michigan, Pennsylvania and Wisconsin are those most likely to see a delayed shift toward Biden once mail-in votes are tallied, which can't start early.

“One concern is that if political figures or the media decide to call the election based on what we’re seeing on election night, and then there’s a change, a swing towards Joe Biden later that this might be problematic because these people might be concerned and it might undermine the belief in a fair election system,” Ognyanova said.

“It’s important that we wait until the counting is done and really announced. I know that people are used to getting results on election night and knowing what happened before they go to bed that day, but I don’t think it’s going to happen this time,” she said. “... We should be prepared to wait for quite a long time before we know what actually happened in the election.”

More From Townsquare Media News: