Calculating the importance of a political endorsement can be as tricky as trying to determine whether a glass is half empty — or half full.

Two veteran analysts of Boston politics told GBH News that Thursday's Boston Globe endorsement of City Councilor Andrea Campbell for mayor is a glass that’s half full.

In a tightening race with many voters still undecided, Erin O'Brien, associate professor of political science at the University of Massachusetts Boston, said the Globe endorsement could make a difference "as many Bostonians are trying to choose between two or three candidates they actually like."

"Most endorsements operate in a hyper-partisan climate where minds are made up," she said. "The Globe's endorsement will matter at the edges — another consideration to help potential voters decide."

This, O'Brien said, is especially true among the field of the five highest-profile candidates.

The most recent mayoral poll, from 7News and Emerson College, found the front runner to be City Councilor Michelle Wu, followed by Councilor Annissa Essaibi George, acting Mayor Kim Janey, Campbell and, polling in single digits, former economic chief of development John Barros.

When the potential margin of error is taken into account, Essaibi George, Janey and Campbell were running neck and neck. The poll suggested that Janey had lost support and Campbell gained.

But O'Brien was struck by the number of undecideds: about 25%.

"I've said for months, it's a jump ball," said Lawrence DiCara, a former Boston City Councilor and one-time mayoral candidate.

DiCara said he’s seen a lack of voter decisiveness: "I think any of the four [women candidates] could be in the final."

The Globe endorsement, he said, could also go a long way in shoring up voters' outstanding questions about Campbell's viability.

"Andrea has been biting at the heels of Kim," DiCara said, pointing to the polling shift.

DiCara noted that in an historic field where the five leading candidates are people of color, and two of the most visible — Janey and Campbell — are Black women, the Globe endorsement could play an important role in helping voters to make a final decision in the Sept. 14 preliminary election.

Earlier in the campaign, Campbell publicly decried an email suggesting that she exit the race to clear a path for Janey.

"There's a lot of complicated feelings that people have, in part because this is the first time we're not going to have a white male since the first white male became mayor exactly 200 years ago," DiCara said.

He cautioned, though, the endorsement is not a "slam dunk."

In 2013, the Globe made a dual endorsement in the primary of John Barros, who placed sixth, and of John Connolly, who advanced to the general election but narrowly lost to former mayor Marty Walsh.

"We're going to know in twelve days," DiCara said Thursday night.