Jonathan Gruber is an economist from MIT. Jonathan Oberlander is a political scientist from the University of North Carolina. Both are health policy experts—and, from what we can tell, both know their stuff. But the press has counted on Gruber rather than Oberlander to give gravitas to their stories. A Factiva search on Monday showed that from January 1, 2009 until January 25, 2010, Gruber got 386 media mentions, compared to thirty-seven for Oberlander. The relative obscurity of Oberlander prompted us to feature him last May in one of our Excluded Voices posts.

Since the beginning of the health reform debate, Campaign Desk has noticed that the media relies way too much on the same sources, who utter the same thing again and again to different news outlets. The problem with this, of course, is that a particular view of the world spreads widely, perhaps reinforcing that view as the correct one—which it may or may not be, depending on the facts and on which side of the river you call home.

Gruber has been the cheerleader-in-chief for the Massachusetts health care plan, which is the model for federal reform. He sits on the board of the Connector, the state’s policy brokerage service, and thus has something of a vested interest in positively spinning the reform efforts there. Last year on the PBS NewsHour, he told how premiums for individuals buying their own coverage in Massachusetts had dropped dramatically. But he didn’t mention how premiums for workers in small businesses had risen to sky-high levels in order to make that possible.

According to a Wall Street Journal op-ed by then-Gov. Mitt Romney, written shortly after the law passed in 2006, Gruber’s econometric research predicted the state would need “far less” than the $1 billion in its free care pool in order to subsidize the insurance residents were required to buy. We now know the state has come up short, and has had to raise taxes and increase copayments and premiums for those receiving subsidies to help cover the shortfall.

So much for assurances! That hasn’t stopped Gruber from giving them in the nation’s news columns and on the editorial pages. In November, he was quoted on The Atlantic’s Web site saying it’s “really hard to figure out how to bend the cost curve, but I can’t think of a thing to try that they didn’t try.” He said the bill drafters made the best effort anyone has ever made. Around the same time, New York Times columnist David Leonhardt let Gruber offer his thoughts on cost containment. In one column, Gruber said that the Senate bill did considerably more to control costs than he had expected.

As the excise tax on the so-called Cadillac health insurance plans became the financing method of choice to subsidize the uninsured, Gruber again became the media’s go-to guy for comments. In July, he penned a Times op-ed arguing to eliminate the tax exclusion for employer-sponsored insurance. Some experts believe that the excise tax on Cadillac plans is the first step toward wiping out the exclusion in the future.

In late December, he wrote another op-ed, this time for The Washington Post, arguing that the excise tax provides the necessary financing for subsidies, induces employers to buy more cost-effective health insurance, lowers U.S. health care spending, offsets a bias in our tax system that favors expensive insurance, and raises wages by $223 billion over ten years—another carefully researched prediction, perhaps? Gruber appeared again on the News Hour in early January, where he said the excise tax is “generally viewed as one of the very few things we know can actually help with health care cost control, which is an important goal of this bill.”

Trudy Lieberman is a fellow at the Center for Advancing Health and a longtime contributing editor to the Columbia Journalism Review. She is the lead writer for The Second Opinion, CJR’s healthcare desk, which is part of our United States Project on the coverage of politics and policy. Follow her on Twitter @Trudy_Lieberman.