New voters pulled counties toward Biden in 2020, and did nothing in 2024

In 2020, counties with a larger share of new voters swung further toward Joe Biden. The county-level correlation between the share of new voters and the presidential swing was 0.42 across North Carolina’s 100 counties and 0.50 across Ohio’s 88. For new unaffiliated voters in North Carolina it was 0.71. In 2024 the relationship disappeared: −0.10 in North Carolina and −0.03 in Ohio.

A new voter here is someone who voted in that general election with no earlier general-election vote on their state record.

What it means

New voters mattered to the 2020 swing in a way they did not in 2024. In 2020, where more people were voting for the first time on record, the county moved further toward the Democratic candidate. In 2024, the counties with many new voters swung about as much as the counties with few.

The 2020 effect was strongest among new unaffiliated voters in North Carolina. Unaffiliated voters were the largest group of new voters that year: 487,207 of 1,246,188, against 380,488 Democrats and 378,493 Republicans.

New voters were also a large part of both electorates. In North Carolina they were 22.5% of 2020 voters and 16.1% of 2024 voters. In Ohio, 11.0% and 7.7%.

For 2026, this is a warning against assuming that a surge of new voters favours one side. It did in 2020. It did not in 2024.

What it doesn’t mean

It does not show how new voters voted. A correlation across counties says that places with more new voters swung more. It cannot say whether the new voters themselves caused the swing, or whether something else about those counties did. No official record shows individual votes.

It does not extend to midterms. We measured presidential swings only. New voters are a much smaller share of midterm electorates: 7.5% of North Carolina’s 2022 voters, and 3.1% of Ohio’s.

“New” is limited by the records. North Carolina’s history file starts in November 2016, so a 2020 “new” voter may have voted before 2016. Ohio’s file holds only voters registered today, so people who have since moved, died or been removed are missing, and the gap grows the further back the year is.

Party means different things in the two states. North Carolina records party registration at the time of voting. Ohio has no registration, so party there is the last primary ballot, and most voters have none.

How we checked

For North Carolina we used the State Board of Elections statewide voter history and registration files, both dated Oct 18, 2026. Each voter was matched by ID across general elections from 2016 to 2024 and counted by county, party and whether they had voted in an earlier general.

For Ohio we used the Secretary of State’s statewide voter file, last updated Oct 17, 2026: 8,015,003 voter records with general-election columns back to 2000. A voter is new if no earlier general-election column is filled.

For each state and year we correlated each county’s share of new voters with the county’s change in the Democratic presidential margin from the previous election. Only county counts were kept; no voter-level data was stored.