First there was March 1: With more than a dozen contests and the most delegates at stake of any day in the presidential race, the original Super Tuesday gave big totals to billionaire Donald Trump and former Secretary of State Hillary Clinton. Then came March 8, when four states voted on the Republican side, three of which landed in the Trump column. Now comes the primary season's third big night, when five states—Florida, Ohio, Illinois, North Carolina, and Missouri—go to the ballot box, including four of the 10 most populous in the country. The first two states are winner-take-all for the Republicans, which could help Trump break away from his rivals. Who will win? Here are seven indicators.

PredictWise: Trump and Clinton

The research project led by David Rothschild, an economist at Microsoft Research in New York City, which aggregates betting-market data and polling, has successfully predicted the winner in 35 of 46 individual nominating contests so far this year. As of Sunday, PredictWise had Trump up in four of five states—all except Ohio, where home-state governor John Kasich is at 70 percent. Texas Senator Ted Cruz was narrowly favored in Missouri as of the end of last week but ceded the top spot to Trump and now has a 39-percent chance of winning. Senator Marco Rubio's 12-percent odds in his home state of Florida could spell the end of his presidential bid.

On the Democratic side, Clinton is also expected to win four of five states, according to the PredictWise model. She has a greater than 85-percent chance of winning delegate-rich Florida and North Carolina, plus a 65-percent chance of winning Ohio. Clinton is also narrowly favored (53 percent) in Illinois, where she grew up, while Senator Bernie Sanders has a 56-percent probability of victory in Missouri.

RealClearPolitics: Trump and Clinton

As of Sunday, the poll averaging and aggregating site had Trump ahead in Illinois, North Carolina, and Florida—three of the four states that have been polled regularly in March. Rubio faces an 18-point deficit in Florida. In Ohio, Kasich had a two-point lead. Among Democrats, Clinton was ahead in all four states that have been polled regularly. 

Bing: Trump and Clinton

With a roughly 75-percent accuracy rating so far this cycle, Bing Predicts expects blowouts for Trump and Clinton on Tuesday. Trump is forecast to win every state except Ohio, according to the “machine-learned predictive model” that the Microsoft search engine created. It parses data from polls, prediction markets, search engine queries, and social media posts.

Clinton, meanwhile, is expected to win roughly 60 percent or more of the vote in every state except Missouri, which Sanders is predicted to take.

FiveThirtyEight: Trump and Clinton

On Sunday, FiveThirtyEight, which is run by former New York Times stats guru Nate Silver, gave Trump odds of winning Florida, Illinois, and North Carolina. As in other models, Ohio is expected to go to Kasich. (The site wasn't able to model Missouri because of a dearth of polling.) Rubio has just a 2-percent chance of winning his home state of Florida when looking at recent state polls; his chances increase to a still-insufficient 10 percent when national polls and endorsements are factored in. Kasich has a 78-percent chance of winning Ohio, with Trump coming in second.

For the Democrats, Clinton has a 95-percent-or-greater chance of winning Tuesday's four big delegate prize states—Florida, Illinois, North Carolina, and Ohio—according to the FiveThirtyEight model, and an 81-percent chance of taking Missouri.

(For each state, FiveThirtyEight uses two models, one that averages polls and one that attempts to combine the effect of endorsements with the polls. Odds sometimes vary between the projections, but for all states, the candidate who has the highest chances of winning in one model has the highest chances in the other.) 

Political Insiders: Toss-Up and Clinton

Kasich's 60 home-state endorsements, including from Senator Rob Portman, give him the overall lead in lawmaker support across March 15 primary states. By Bloomberg Politics’ latest count, Kasich also has the most total Illinois endorsements, with nine state legislators publicly backing him, while Rubio has the support of Illinois' congressional delegation (or three of its members, at least). Rubio leads in terms of Florida, North Carolina, and Missouri endorsements. As for Trump, he has yet to announce a single legislator supporting him from any of the five states voting on Tuesday.

The Democratic endorsement ledgers are far more lopsided. According to a tally updated by FiveThirtyEight, Clinton is publicly supported by 25 U.S. representatives from all five March 15 states, four senators (including Missouri's Claire McCaskill, who endorsed Clinton back in June 2015), as well as Missouri's governor. In comparison, Sanders has notched just two congressional endorsements. 

Endorsements from elected officials have historically been among the best available indicators of success in a party primary, though that pattern been challenged by the 2016 Republican race.

Ballotcraft: Trump and Toss-Up

This fantasy politics game, which was co-founded by two Stanford grads, has thousands of players who use fake money to buy “shares” in candidates. So far, it has correctly predicted 37 of the 46 nominating contests it has covered. As of Sunday, Trump was expected to win three of five states: Florida, North Carolina, and Illinois. Cruz is most competitive in Missouri, where the site's users give him a 57-percent chance of winning. Rubio has just a 33-percent chance in Florida, whereas Ohio Governor John Kasich is given 68 percent odds of finally winning his own home state, which would be his first win.

On the Democratic side, Clinton is likely to sweep the Southern states (Florida and North Carolina) but is at risk of losing the Midwest states. “Neither of the candidates is a strong favorite in any of those contests, with odds less than 65 percent for the favorite in all five,” according to Ballotcraft CEO Dennis Jiang. “The reason for this ambivalence is twofold: there's been less polling for these contests and Sanders’ massive upset in Michigan last week has left our users less confident in the predictive power of primary polling overall.” 

State-by-State Tally

Here's a detailed look at what each source says about the primaries on the Republican side.

And a look at what each source says to expect on the Democratic side.

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