NEW HAMPSHIRE — Over the last week, much of the nation’s political press corps has headed to Iowa to cover the Republican presidential campaign. The saturation coverage is already reaching absurd levels. Scott Conroy of Real Clear Politics described a Mitt Romney event Sunday in Atlantic, Iowa as “45 journalists, 30 Iowans, [and] 20 out of state political tourists.” According to The Associated Press, “scores of reporters, photographers and camera crews packed into a small restaurant” there, “making it impossible to tell how many Iowa voters were seated at the tables.”

With so many journalists covering the Iowa caucuses, the media tends to invest the outcome with a great deal of importance—in particular, by creating a narrative about the “meaning” of the results for the candidates going forward. Though this interpretive process helps both voters and party leaders coordinate in supporting the most competitive candidates, it also creates important challenges for reporters here in New Hampshire and nationwide who will cover the race as it moves forward after Iowa.

First, the good news. While it may be democratically dubious to give such disproportionate weight to a few small states, early primaries and caucuses do play a crucial role in the primary process, by giving Republicans (or Democrats) useful information about the candidates vying for their nomination. As the political scientist Jonathan Bernstein has argued, the function of these early contests is to “produce the information that party actors want [about candidate viability], do so in a timely way that allows them to incorporate that information into their decisions, and allow for coordination and orderly competition by party actors.” In this way, both elites and citizens who wish to cast their votes strategically can coalesce around the candidates who perform best.

Unfortunately, the “meaning” of the caucus results is not always clear. These rough edges are typically sanded away in post-Iowa reporting and commentary, however, which tends to emphasize the order of the finish (even when the margins between candidates are small) as well as unexpectedly weak or strong results. Media outlets then shift energy and resources toward candidates who performed well under the prevailing interpretation, while ignoring or providing negative coverage of those who were believed to have done poorly. These shifts in coverage, which themselves become part of the information party leaders are responding to, can help create massive post-Iowa swings in a candidate’s chances (PDF).

The result is a refraction effect in which journalists help make Iowa influential and then report on its “effects” without acknowledging their role in the process or the often arbitrary nature of the distinctions that are made among the candidates. This is a recurring problem—the norms of journalism demand that reporters exclude themselves from the stories they write, creating a troubling lack of self-consciousness about their own role in the process. (Consider, for instance, New York Times reporter Jeff Zeleny building a recent story around Romney calling Newt Gingrich “zany” without ever mentioning that it was Zeleny who first applied the term to the former House speaker.) But these incentives are especially problematic in campaigns since journalists have a strong rooting interest in continued conflict and dramatic storylines.

In this case, it appears very likely that Mitt Romney will ultimately win the Republican nomination (the current odds on the Intrade futures market, which are arguably too low, put him at 79%). However, the post-Iowa narrative is likely to emphasize any weakness in Romney’s performance and hype those rivals who perform well, no matter how strong the evidence for those propositions.

Here in New Hampshire, for instance, local TV heavyweight WMUR and the Concord Monitor are already anticipating the “Santorum surge” foreshadowed by a recent Des Moines Register poll, which placed Romney first, Ron Paul second, and Rick Santorum third. A third-place Santorum finish is likely to generate a wave of positive coverage about his “momentum” even though there is little indication that the former Pennsylvania senator has the financial or organizational capacity or the broad base of party support necessary to compete nationally with Romney (as Ezra Klein notes, Intrade puts his chances at 4%). Likewise, if Romney is edged out for first place by Paul or Santorum, the resulting coverage will almost surely overhype the result as signifying a more general weakness of his campaign despite the likely eventual outcome of the race.

The result in Iowa is genuinely significant because of the weight it is given by party actors, but journalists should recognize that “momentum” is a subjective interpretation of the results that they help to create. Reporters in New Hampshire and other early states ought to think carefully about how to select and frame their post-Iowa stories rather than passively accepting the conventional wisdom about the state of the race.

Brendan Nyhan is an assistant professor of government at Dartmouth College. He blogs at brendan-nyhan.com and tweets @BrendanNyhan.