More than 100 mayors — including several black mayors — have now endorsed Mike Bloomberg for the Democratic nomination for president. The list includes such prominent African American mayors as Vi Lyles of Charlotte; London Breed of San Francisco; Muriel E. Bowser of Washington; and Sylvester Turner of Houston.

Some observers were surprised, because Bloomberg has been widely criticized for racially tainted policing practices and has only recently apologized for supporting the discriminatory practice of stop-and-frisk. Others see the endorsements as suspect, because Bloomberg’s foundation funded either training and support for these mayors or projects in their cities in the past few years.

So, will these endorsements make a difference to voters?

Endorsements matter — some more than others

Some observers dismiss endorsements, believing that voters are uninformed and often unaware that they have been made. But my research shows that voters in places such as North Carolina are well aware of major endorsements, even in municipal elections.

Further, black and Latino voters often use endorsements in their local elections as they cast their ballots for mayor, as I found in researching my book. Black voters use endorsements from black organizations to help them decide for whom to vote, especially when race is an important factor in the election — as it is in the 2020 presidential contest.

But not all endorsements are created equal. My research highlights four issues in particular to consider.

1. What do these endorsements mean to the voters?

The research suggests that voters are open to considering endorsements when they cast their ballots. This doesn’t mean that all voters always turn to endorsements to guide their decisions, but under the right conditions, voters treat endorsements as useful pieces of information.

For example, my research shows that black voters rely on black leaders’ endorsements primarily when racial inequality becomes an issue in a campaign. At that point, they look for community leaders’ cues about whether a particular white candidate can be trusted. I used survey experiments to test the relationship between endorsements and candidate preferences. In one in-person experiment (with a convenience sample of 266 black respondents), I had respondents read about a fictional campaign for a mayoral election in which three factors varied randomly: whether the candidate was white or Latino; whether racially charged issues were discussed in the campaign; and whether black leaders endorsed the candidate.

Respondents were more likely to support the endorsed Latino candidate, regardless of racial issues. But they paid attention to the white candidate’s endorsements only if race was a campaign issue. In a second experiment, I replicated my results using a national sample acquired through GfK (formerly Knowledge Networks) that included 317 whites, 214 blacks and 204 Latinos.

Further, in the 2018 Cooperative Congressional Election Study, I asked 1,000 respondents (719 white, 89 black, 81 Latino, the rest other) which endorsements would make them more likely to vote for a congressional candidate; between 19 percent and 22 percent said they would be influenced by local newspapers or elected officials, while 25 percent said they would pay attention to Black Lives Matter or another “progressive organization.”

2. What do the endorsements mean to the candidates?

A thumbs-up from a respected community leader lends candidates credibility among groups whose votes they need.

So it’s unsurprising that former South Bend, Ind., mayor Pete Buttigieg, who has had trouble attracting black voters, has been trying to get more attention for the endorsements he has gotten from black leaders. Other candidates, including Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.), are talking explicitly about race — and relying on women of color to actively campaign for them. Rep. Alexandria Ocasio-Cortez (D-N.Y.) is making high-profile campaign appearances for Sanders, and Rep. Ayanna Pressley (D-Mass.) has been campaigning for Warren.

3. What do the endorsements mean for the endorser?

Why do leaders and organizations endorse a candidate? Those motivations can vary. Organizations, institutions and interest groups have the resources to research candidates’ positions and attitudes in a way that the average voter cannot. With that information, those groups may wish to persuade voters to cast ballots for the candidate most likely to advance the group’s goals.

Motivations can be different for various community leaders. For the mayors endorsing Bloomberg in particular, some may feel they have unique insight into their former fellow mayor, believing that his skills and experiences would help him be a good president. Others may be placing a bet on who’s likely to win, hoping to be appointed to a position in the administration. Or mayors may be hoping that a former mayor will fund cities more generously than have other administrations. If that’s so, the mayors may reason, their cities’ residents may be grateful that their mayor has helped the city.

4. How do voters learn about endorsements — and which ones get attention?

Of course, the media pay more attention to some endorsements than to others, which can deprive voters of information that might sway their thinking. For example, Warren has been endorsed both by an activist organization called Black Womxn For, but FiveThirtyEight’s list of endorsements mentions only individuals. And yet my research on local organizations and endorsements suggests that the organizational endorsement might matter more to black voters. This is likely for two reasons. First, the organization usually learns about candidates’ positions by interviewing them or having them complete questionnaires. Then, the members of the organization vote on who to endorse, giving members a stake in those endorsements. Second, once the endorsement is issued, the organization often works for the candidate by sending out mailers or having volunteers make phone calls and knock on doors. Although an elected official’s endorsement may influence some voters, without the media coverage, the voters may not even know about the endorsements.

What does this mean for Bloomberg’s mayoral endorsements? Race is most certainly an issue in 2020, with most Democratic voters — black voters included — focused on who can defeat President Trump in November. Will Bloomberg’s mayors outweigh Warren’s and Sanders’s visible surrogates, Warren’s endorsement by Black Lives Matter’s fund Black to the Future or longtime South Carolina Rep. James E. Clyburn’s forthcoming endorsement? We may find out when South Carolina votes on Saturday — or on Super Tuesday on March 3.

Andrea Benjamin (@ProfBenjamin) is an associate professor in the Clara Luper Department of African and African American Studies at the University of Oklahoma and author of “Racial Coalition Building in Local Elections: Elite Cues and Cross-Ethnic Voting (Cambridge University Press, 2017).