RALEIGH, N.C. (WNCN) — Approval ratings for state governors and world leaders rose as the number of cases of COVID-19 climbed, according to a study co-authored by a University of North Carolina doctoral student.

The study pointed to the concept of rallying around the flag — in which people support their leaders in times of crisis. It’s usually seen during wars or after terrorist attacks, with the study marking perhaps its first prevalence in a public health emergency.

Published in Proceedings of the National Academy of Sciences, it might shed some light on an advantage for incumbents in this year’s election.

“We really didn’t know if it would translate to a health crisis or not, or whether it would translate beyond the U.S.,” said Joshua Jackson, the Ph.D. student at UNC who is one of the study’s six authors and conducted the data analyses. 

“And we thought that it might be kind of strange if it did, because of how leaders have been critiqued for how they’ve handled the virus,” he added. “The effect really surprised us with how strong it was. To put it into perspective, the magnitude of this effect was stronger than the correlation between height and weight, which is a really robust correlation.”

The study found daily approval ratings for leaders of 11 countries — including the United States, Canada, Mexico, the United Kingdom and Germany — increased on average by 14 percent earlier this year. Weekly approval ratings for all 50 state governors climbed by an average of nearly 20 percent during the time period measured.

The authors measured the governors’ approval and disapproval ratings weekly from Jan. 1 through May 11, used daily ratings for 10 world leaders from Jan. 1 through April 30 and for Hong Kong used daily ratings from Feb. 3 through April 30.

It found that on average, an increase of more than 1,995 new cases would translate to a point of approval for a world leader, and an increase of 5,305 new cases would translate to a point of approval for a state governor.

“We therefore predict that COVID-19 cases should be linked with higher levels of support for national leaders, regardless of their performance in handling the pandemic,” the authors wrote.

The trend cut across party lines, with Republican governors of states that voted for 2016 Democratic presidential nominee Hillary Clinton seeing bumps along with Democratic governors of states won by Republican Donald Trump four years ago, Jackson said.

One of those states is North Carolina, which turned red in 2016 but where Democratic Gov. Roy Cooper saw a net increase of 20 points, Jackson said, with Cooper’s approval rating increasing by 15 points.

Cooper, who is seeking re-election, leads Republican Lt. Gov. Dan Forest in a CBS 17/Emerson College poll released Friday.

“It shows how this effect cuts across political partisanship,” Jackson said. “We saw it both for Republican governors in predominantly Democratic states and for Democratic governors in predominantly Republican states, along with same affiliation governors.”

Jackson said Trump saw an increase of 4 percent for his handling of the coronavirus crisis, ranking him in the middle of the pack. Australian Prime Minister Scott Morrison and Germany’s chancellor, Angela Merkel, experienced significant increases while leaders in Japan and Brazil saw declines.

“(Trump) wasn’t the strongest, of course, but he still experienced a significant bump that was beyond the margin of error in our models,” Jackson said.

There are some limitations. The authors say Trump’s approval rating has dropped since they collected their data and they can’t determine whether that is if “the rally effect decays over time” or if people became “more sensitive to how leaders have handled a threat.”

And while they can’t say if the “rally effect” will last through November, Jackson says the findings of the study “could have really dramatic effects.” In South Korea’s election in April, the incumbent party won the most seats in the house by any party since 1960.

“I don’t think it can be overstated,” he said, “because you’re already seeing election being won by huge numbers by incumbent parties.”