About one-fifth of potential voters in next week’s presidential primary weren’t here in 2020 or couldn’t vote in the last primary, according to a UNH study, reflecting the fact that while New Hampshire’s population isn’t growing very fast, it is continuously changing.

In the past four years, according to the state analysis published Tuesday, New Hampshire gained 245,000 potential new voters, some of them newcomers moving to the state and some of them people who reached voting age. In the same period, 208,000 longtime residents left the state or died. As a result, 22 percent of potential Granite State voters were either too young to vote (6 percent) or did not live in New Hampshire (16 percent) in 2020.

“That’s a lot of turnover in a state with roughly 1.1 million people who could potentially vote,” said UNH professor Kenneth Johnson, one of  three authors of the report.

 The report, co-authored by UNH professors Andrew Smith and Dante Scala, says “the ideology and political party allegiances of these young people and new migrants differ significantly from those of longtime residents.”

“In particular, both groups are more willing to take sides rather than adhere to the political center. For instance, nearly 64 percent of the young potential voters are attracted to left-leaning ideologies, describing themselves as either liberal, progressive or socialist. Regardless of their preferred ideological label, young voters are far more likely to identify as Democrats or Independents than as Republicans.

“In contrast, newcomers are more evenly split between ideologies of the left and right, although Democrats enjoy a modest advantage among these recent migrants. … Relatively few describe themselves as moderates, especially as compared to established voters who make up 78 percent of the electorate.”

Demographic data for this study come from the U.S. Census Bureau’s American Community Survey and the 2023 Population Estimates. Data on political ideology are derived from the Granite State Poll collected in 2023.