At Hillary Clinton’s Super Tuesday victory rally in Miami, the handmade signs hanging just off the stage delivered a succinct message: Vote Early.

Florida holds its primary election on March 15 but voters there could begin casting ballots Feb. 29. Of the 28 states that host March nominating contests, nearly a third have some form of early voting.

Clinton’s campaign has invested heavily to encourage voters to cast early ballots, particularly in delegate-rich states such as Texas, which she won by a large margin on Tuesday.

The strategy makes sense, according to research done by Randolph-Macon College Professor Elliott Fullmer, who told Reuters early voting tends to benefit well-known front runners such as Clinton, a former secretary of state, U.S. senator and first lady.

“A campaign like Bernie Sanders’ is likely to have more room to grow once they enter a state,” Fullmer said of Clinton’s opponent. “I certainly wouldn’t be surprised, on Super Tuesday or in other March contests, if Clinton can gain an advantage by virtue of early voting.”

Late-deciding voters indeed seem to have made a difference on Super Tuesday, with Republican Marco Rubio winning many at the expense of Donald Trump–perhaps a sign that the Florida senator’s assault on Trump’s character may have had some impact.

Fullmer said that in Clinton’s 2008 race against now President Barack Obama, then a relatively unknown U.S. senator, data from California, Arizona, Tennessee and Florida showed that an early voter was 7 percentage points more likely to back Clinton than one voting later on.

In Texas, which had the most delegates up for grabs Tuesday, more than 12 percent of registered voters cast early ballots from Feb. 16 to 26. Clinton’s campaign organized at least 15 events the day before kickoff. Supporters gathered for “early vote together” events in Dallas, Houston and San Antonio the first day. Clinton flew to Texas on Feb. 20 after winning the Nevada caucuses to hold a rally during early voting.

In Georgia, which Clinton also won by a large margin on Tuesday, voters could begin casting ballots 21 days in advance. The campaign took note, with the candidate hosting a kick-off event, calling into a local radio program to push early voting and headlining an early-voting rally in Atlanta.

One example: Rosa Abrams, 60, voted early in Augusta last week – and her ballot underscored how the combination of an accelerating election calendar and early voting might benefit Clinton throughout March.

Abrams preferred Clinton’s policies, saying “she’s just got the experience dealing with foreign countries and all of that,” she said.

Abrams told Reuters she decided who she was voting for three months ago.