Want a secret weapon for succeeding in the New Hampshire primary? Be a politician from a neighboring state. Want a secret weapon for succeeding in the Iowa caucuses? I’m afraid it’s back to the drawing board; hailing from a nearby state doesn’t look like much of a help.

Historically, candidates from neighboring states have had a checkered record in the Iowa caucuses, in contrast with the clear home-field advantage that exists for candidates from next door to the Granite State. In total, I identified 17 “major” candidates from Minnesota, Wisconsin, Illinois, Missouri, Nebraska, South Dakota or Iowa itself who have run in the caucuses since the modern primary era began in 1972, but only six of them won at least 20 percent of the vote and finished in either first or second. The 11 other candidates flopped, receiving 11.2 percent of the vote or less. One candidate even finished in eighth. (For comparison, in New Hampshire, politicians from neighboring states have always finished in the top two.)

Iowa doesn’t care where you’re from “Major” presidential candidates from Iowa or neighboring states who have run in the Iowa caucuses, since 1972 IA Caucus Result Year Party Candidate Home State Vote Share Finish* 1972 D George McGovern South Dakota 22.6% 2nd 1972 D Hubert Humphrey Minnesota 1.6 3rd 1972 D Eugene McCarthy Minnesota 1.4 4th 1980 R Phil Crane Illinois 6.7 5th 1980 R John Anderson Illinois 4.3 6th 1984 D Walter Mondale Minnesota 48.9 1st 1984 D George McGovern South Dakota 10.3 3rd 1984 D Jesse Jackson Illinois 1.5 7th 1988 D Richard Gephardt Missouri 31.3 1st 1988 D Paul Simon Illinois 26.7 2nd 1988 D Jesse Jackson Illinois 8.8 4th 1992 D Tom Harkin Iowa 76.4 1st 1992 D Bob Kerrey Nebraska 2.4 4th 1996 R Maurice Taylor Illinois 1.4 8th 2004 D Richard Gephardt Missouri 11.2 4th 2008 D Barack Obama Illinois 37.6 1st 2012 R Michele Bachmann Minnesota 5.0 6th “Major” candidates were those included in national polls * Among named candidates — i.e., not counting “uncommitted.” Sources: State of Iowa, Des Moines Register, CQ Press, New Hampshire secretary of state

Why doesn’t it help to be from next door in Iowa when it is such a clear advantage in New Hampshire? I have several theories, but first things first — it is probably in part because candidates from around Iowa are just weaker candidates overall than candidates from around New Hampshire.

For instance, I found that the national polling average of Iowa-native and Iowa-adjacent candidates in the 30 days leading up to the caucuses was 11 points, on average, but for New Hampshire-adjacent candidates, it was nearly double that at 21 points.

But that’s not all that’s going on here. New Hampshire-adjacent candidates also did much better (19 points better, in fact) in the New Hampshire primary than their national polling average in the 30 days leading up to the primary. In Iowa, local candidates overperformed, but not by nearly as much. On average, these candidates did just 6 points better in the caucuses than they did in an average of national polls conducted in the 30 days before the caucuses — and that includes one candidate, then-Sen. Tom Harkin in 1992, who improved upon his national polling average by 70 (!) points in Iowa. (Harkin is the only major presidential candidate in the modern era actually from Iowa, so it’s not necessarily that surprising that he basically scared the other Democratic candidates away from competing there.) If we remove Harkin from the equation, Iowa-adjacent candidates’ advantage falls to 3 points, on average. That’s barely any better than the 1 percentage point by which candidates not from the area overperformed their national polls in Iowa, on average.

The reason home-field advantage is weaker in Iowa than in New Hampshire may be that many of the factors that make local candidates strong in New Hampshire do not carry forward to Iowa.

Distances, for instance, are longer in the Midwest than in New England, so it is not as easy for candidates from neighboring states to just pop in to Iowa for a quick visit.

Additionally, whereas a majority of New Hampshirites were born out of state, 70 percent of Iowans were born in Iowa, according to 2017 estimates from the American Community Survey. Only 4 percent were born in Illinois, 3 percent in Nebraska, 2 percent in Minnesota and 1 percent in each of Missouri, South Dakota and Wisconsin. In addition, only 5 percent of Iowa workers aged 16 or higher cross state lines to go to work.

Most Iowans — 66 percent — live in a broadcast media market (either Des Moines-Ames or Cedar Rapids-Waterloo-Iowa City-Dubuque) that is wholly contained within the state, meaning there is no real reason for its news coverage or political advertising to feature politicians from neighboring states. Only 15 percent live in a media market shared with Nebraska, 12 percent live in a media market shared with Illinois and even fewer live in media markets shared with other nearby states. (For comparison, 84 percent of New Hampshirites live in the Boston media market.)

This is admittedly subjective, but I would also say that New England has a more uniform identity than the Midwest does. State borders seem to matter more in the Midwest (for example, most of New England roots for the same sports teams, but that is not true of the Midwest), and the Midwest is more heterogeneous. Perhaps this is why some candidates from neighboring states outperformed their national polls in Iowa, and others did not.

As for this year, the question of whether home-field advantage exists in Iowa might not matter much. That’s because there aren’t any candidates from Iowa currently running for president. There is one major presidential candidate from a state that borders Iowa: Minnesota Sen. Amy Klobuchar. And she does appear to be putting a lot of her eggs in Iowa’s basket. But unfortunately for her, merely being from next door does not appear to give a candidate much of a boost in the Iowa caucuses. In fact, Klobuchar’s fellow Minnesotans (Hubert Humphrey, Eugene McCarthy, Walter Mondale and Michele Bachmann) have all done worse than their national polling average there.

Geoffrey Skelley contributed research.