With the Iowa Caucuses less than two months away Donald Trump is currently the leader in the race for the Republican Party nomination according to a new computer model that takes into account current polling and endorsements for the major candidates. An algorithm designed to weight both the polls and the endorsements received by the major candidates gives Trump a 30 percent chance of winning the Republican primary, compared to 22 percent for Marco Rubio, 18 percent for Ted Cruz, 16 percent for Jeb Bush, and 14 percent for Ben Carson. The algorithm takes into account polls released from a variety of sources, including polls released yesterday by USA Today, CNN, Monmouth University, and Investor’s Business Daily.
The algorithm works by giving a certain weight to a number of factors in calculating the odds that each candidate will eventually win the Republican Party nomination. The heaviest weight, 30 percent, is given to the New Hampshire primary, which has tended to be the most predictive contest over the last 20 years. Other factors included are polling of the Iowa Caucus (20 percent), South Carolina primary (10 percent), and nationwide polling (20 percent). Finally, to account for the effect of the party establishment and super delegates a 20 percent weight is given to the number of endorsements candidates have received using FiveThirtyEight’s measurement of official endorsements for each candidate.
At this time only Donald Trump, Ben Carson, Ted Cruz, Marco Rubio, and Jeb Bush are included in the calculations, as all other candidates are polling too low in Iowa, New Hampshire, and the general electorate to be considered a serious threat for the nomination. Chris Christie is close, and if he can continue to rise in the New Hampshire polling he will soon be included in the projections as well.
So what do the polls say?
A Real Clear Politics average of four New Hampshire primary polls gives Trump the lead with 28.3 percent support. Marco Rubio comes in second with 12.3 percent of the vote, and Ted Cruz places second with 9.5 percent support. Cruz is surging in Iowa, with some polls now putting him ahead of Trump. However, often the winner of Iowa ends up failing to win the Republican Party nomination. In 2012 Rick Santorum won Iowa and in 2008 it was Mike Huckabee. Both men were eventually overcome by the winners of the New Hampshire primary, Mitt Romney in 2012 and John McCain in 2008. Unless challengers can chip into Trump’s lead in New Hampshire over the next two months there is a good chance he will win the state, and with that victory carry a great deal of momentum into South Carolina and Super Tuesday. Trump’s lead in New Hampshire in the number one reason for his lead in the overall primary forecast.
The Real Clear Politics average of polls in Iowa currently has Trump as the leader with 25.7 percent support, compared to 22.3 percent for Cruz, 15.7 percent for Carson, and 13.7 percent for Marco Rubio. As mentioned earlier, Cruz has been surging in Iowa polls and this contest now holds the key to a potential Cruz Republican Party nomination. If Cruz can win Iowa he will likely gain a bump in the nationwide polling. Cruz is unlikely to win New Hampshire given the current state of polling there, but a victory in Iowa could enable Cruz to win South Carolina and then potentially carry that momentum into Super Tuesday to compete with Trump. A Trump loss in Iowa could hurt his reputation as the Republican frontrunner.
The Real Clear Politics average of nationwide polling currently has Trump as the dominant force with 29.3 percent support, compared to 15.5 percent for Cruz, 14.8 percent for Rubio, and 13.8 percent for Ben Carson. Trump has undoubtedly benefited from the tremendous amount of free media coverage he has received over the last two months and it shows in the current state of nationwide polling.
Finally, the reason Jeb Bush and Marco Rubio still have a chance is the party establishment factor. As documented at FiveThirtyEight.com, citing a study done by four prominent political scientists, significant endorsements from members of the party tend to cause success in primary states. In previous elections the party elites tended to favor one candidate ahead of the Iowa Caucus and New Hampshire primary, and that candidate tended, with few exceptions, to go on to win the party nomination. Using Silver’s measurement of endorsements, which gives more weight to endorsements from U.S. Senators and state governors than U.S. Representatives, Jeb Bush currently wins the endorsement race with 46 points. Coming in second is Marco Rubio with 31 points. Ted Cruz, perhaps suffering from his tendency to make enemies in the Senate, has only 12 endorsement points. Ben Carson and Donald Trump both have 0 points. Other candidates, such as Chris Christie, do have some endorsement points, but as previously mentioned those candidates are polling too poorly to currently be included int he algorithm,
Some may be surprised that Trump is not even more of a favorite to win the Republican Party nomination given his lead in all three polling areas, and his dominant lead in nationwide polling.
The reason Trump is not even more of a favorite at this point is that polling tends to fluctuate wildly in the months before and after the Iowa Caucus in early February. As Nate Silver of FiveThirtyEight points out, many voters still are not paying attention to the 2016 presidential race, and may change their mind in the coming months. Indeed, exit polls from previous elections show that many voters in the Iowa Caucus and New Hampshire primary likely have still not made up their mind on the candidate of their choice. In early December of 2012 Herman Cain was leading nationwide polling of Republican voters, and in 2008 the leader at this point was Rudy Giuliana. Victories in Iowa and New Hampshire tend to change the narrative and give new candidates free and favorable media coverage which can change the nationwide polling numbers dramatically. For all these reasons other candidates, including Jeb Bush, are still given a good chance of overtaking Trump in the coming months.
As the campaign goes on the polling numbers, particularly those in Iowa in New Hampshire, will take on more weight. Right now when putting in the numbers and weighting each contest to the best of our knowledge Trump is the favorite, but other candidates still have more than a fair chance to grab the Republican Party’s presidential nomination.