HAMPAIGN, Ill. -- As the race for the 2016 Democratic and Republican presidential nominations enters the early stages, voters have a large pool of candidates to consider, including 17 declared candidates on the Republican side alone.
The drawn-out primary cycle, scheduled to begin in February 2016 and lasting until June, affords a great deal of influence to a small number of voters in early primary states, such as Iowa and New Hampshire. But according to new research from a team of University of Illinois economists, the sequential election format of the primaries is the best mechanism to select the "Condorcet winner" - that is, the candidate who would prevail in a head-to-head election against any one of the other candidates.
In the paper, co-authors George Deltas and Mattias Polborn studied the trade-offs between voter coordination and candidate quality under different primary election systems.
Using data obtained from Democratic and Republican presidential primaries from 2000-12, Deltas and Polborn ran experiments such as replacing the current primary system with a simultaneous system in which all 50 states voted at once, individually or as blocs.
"In principle, presidential primaries do not have to be organized as a sequence of state-by-state elections," said Polborn, also a professor of political science at Illinois. "There have been calls by some pundits to replace the system with a one-day national primary, and there is also a plan by the National Association of Secretaries of State that proposes to hold four regional primaries, one month apart from each other. We wanted to know how these proposed systems would perform in terms of candidate selection."
The findings show that the current sequential election system results in the "highest probability that the Condorcet winner is elected and the highest expected quality of the nominee," according to the paper. The current primary system raises two distinct problems for voters, Polborn said.
"First, many candidates are largely unknown to a national audience, so voters still need to learn by observing the candidates' performance on the campaign trail and their performance in national debates, both of which often play a major role in influencing voters," he said.
"Second, different groups of voters - socially conservative Republicans, for example - have several candidates to choose from that are ideologically aligned with them. And they will be more successful if they manage to coordinate on one candidate rather than splitting their votes among all of them."
But which candidate primary voters coordinate on is a difficult issue to decide, Polborn said.
"Rushed voter coordination might eliminate a candidate who otherwise would have been a legitimate contender if he or she were seriously considered," he said. "In other words, learning about candidate quality takes time."
Sequential primaries have likely facilitated the victory of candidates who were not the frontrunner at the beginning of the primary season. Polborn cites Barack Obama in 2008 as one such example.
"In a simultaneous election with a large set of candidates, the candidate who would come out on top is often not the best one," Polborn said. "By contrast, sequential elections allow voters to narrow down the field of contenders as a way of avoiding vote-splitting among several similar candidates."
Winning, especially in early primaries, helps a candidate because "it conveys positive information about him to voters in later states," he said.
"To use this 'momentum effect,' candidates will spend a lot of time in the coming months trying to persuade voters in Iowa and New Hampshire, even though the number of delegates distributed in these contests is actually very small."
Although sequential elections allow voters to coordinate and thus avoid that a candidate wins just because his ideological opponents split the votes of their supporters among each other, their disadvantage is that, once coordination has occurred, there's very little chance to correct an error made in early elections, as candidate momentum dominates, Polborn said.
"This problem is quite large, as our empirical results show that the probability of the full-information Condorcet winner dropping out after the first few primaries is substantial," he said. "However, the problem of vote-splitting in a simultaneous primary would be a lot worse than the problem of coordination on the wrong candidate in sequential primaries."
Polborn points to the 2010 Illinois Republican primary for governor as an example of the problem of vote-splitting in a simultaneous election.
"There were seven candidates, but only [state senator] Bill Brady came from downstate, while the remaining serious candidates all came from the Chicago area," he said. "Brady received only 21 percent of the statewide vote and most likely was not the strongest candidate that Republicans could have nominated, but won the primary nevertheless because the Chicago-based candidates split the vote there very evenly. Brady then went on to lose what should have been a very winnable general election for the Republicans."
Another result of the study is the finding that some lagging Democratic and Republican candidates dropped out too late in the presidential primary cycle.
"Individual candidates fail to internalize the negative effects they impose on their party and voters by continuing their campaign," Polborn said. "Parties should therefore nudge candidates into withdrawing earlier than they currently do by, for example, awarding the two leading candidates after a certain number of contests the same number of additional superdelegates for the convention. This would not distort the contest between the two front-runners, but it would make it so a potential third candidate has a more difficult time catching up and therefore might drop out sooner."
The paper will appear in the Review of Economic Studies.
Helios Herrera, of HEC Montreal, was a co-author of the paper.
Editor's note: To contact Mattias Polborn, call 217-333-4595; email email@example.com.
The paper, "Learning and Coordination in the Presidential Primary System," is available online.