WASHINGTON—Reporting the results of Election 2020 will be done differently this year and voters should not expect immediate results, federal Election Assistance Commission officials and two state election officials said Tuesday.

“It is going to be a unique experience and I advise folks to go to sleep early and wake up on Wednesday morning,” EAC Vice Chairman Don Palmer said, “and see how the winds are blowing.”

Ballots are counted differently in each state and these variations will result in significantly different timelines for election results, the election officials said. Especially in states that expect to receive a significant number of mailed ballots after the polls close on election night, results — particularly in tight races or in swing states — could take days to be determined.

“Voters must be patient,” EAC Vice Chair Don Palmer said.

New Mexico Secretary of State Maggie Toulouse Oliver emphasized that “election night results are always unofficial on election night.”

Associated Press Managing Editor Brian Carovillano said that AP, which provides election results used by numerous media outlets around the country, has changed its process for evaluating a winner since the last election. In an effort to get more accurate polling and avoid surprises like President Donald Trump’s win in 2016, the agency has moved away from exit polling in favor of a more extensive survey methodology known as VoteCast.

Carovillano said that the network will not announce a winner in a contest until it is sure of the results.

“AP does not do projections,” Carovillano said, “we only do declarations. You might hear a network make a projection, but we do not declare a winner until we are 100% certain that the trailing candidate cannot catch the leading candidate.”

With another two weeks until Election Day, over 33 million people already have voted, 17 million of whom live in swing states, compared with 6 million at the same time four years ago.

EAC commissioners and Iowa Secretary of State Paul Pate said they also were concerned about problems that could occur with voting in-person on Election Day.

Pate said he was worried about potential social unrest at the polls from protesters who, he said, might “inhibit how we get the votes all back to the courthouse to count them.”