PRAIRIE VILLAGE, KS — “I won’t be running anything else from Stephen Moore.”

So says Miriam Pepper, editorial page editor of the Kansas City Star—and not just because she’s retiring this week. Pepper’s no-Moore stance comes after her paper discovered substantial factual errors in a recent guest op-ed by Moore, the chief economist at the conservative Heritage Foundation.

The episode serves as a cautionary tale for editors navigating the disputes of rival policy advocates—and a case study in the delicate art of running a correction.

It all began a month ago, when the Star ran a piece by the Nobel Prize-winning economist-turned- liberal New York Times columnist Paul Krugman, as it does regularly. The column named Moore as one of the “charlatans and cranks” who have influenced policymakers at all levels to enact low-tax, supply-side economic policies—with ruinous effects, according to Krugman. The sweeping 2013 tax cut in Kansas is only the latest example, he wrote, citing unfavorable economic and fiscal news in the Sunflower State.

After the column ran, Pepper told me, “I was contacted by Moore’s people saying they wanted to run a response.” In the interest of fairness, she agreed.

Moore, formerly of The Wall Street Journal, submitted a version of a column that originally ran in Investor’s Business Daily. Contra Krugman, the column argued that Kansas’s tax-cut experiment needed more time to work, and cited statistics to show that states “following Krugman’s (and President Barack Obama’s) economic strategy are getting clobbered by tax-cutting states.”

The Star ran Moore’s column on July 7. It wasn’t until weeks later that Pepper realized there were problems with it. The bad news came from one of her own columnists, Yael Abouhalkah, who had taken another look at Moore’s op-ed while researching an editorial he was writing, and realized that one key paragraph—the one containing the most specific data in support of Moore’s claim—didn’t check out.

Moore had written:

No-income-tax Texas gained 1 million jobs over the last five years; California, with its 13 percent tax rate, managed to lose jobs. Oops. Florida gained hundreds of thousands of jobs while New York lost jobs. Oops.

The recurring “oops,” intended as a dig at Krugman, took on an unintended irony after Abouhalkah discovered that Moore’s numbers did not match those of the Bureau of Labor Statistics.

In fact, Moore later acknowledged, he was using BLS numbers not from “the last five years” but from an earlier five-year period: December 2007 to December 2012. Focusing on that period is arguably dubious, because the span captures the depths of the Great Recession and the housing crash, which hit some states harder than others—and whose impact likely would have swamped any tax-rate effect. There are other issues with the quality of Moore’s argument, too, like its glancing-at-best treatment of how factors like housing costs shape population and job growth.

In any case, Abouhalkah found, Moore’s numbers were wrong even for 2007-12, in ways that complicated the “low taxes = more jobs” message. As Abouhalkah wrote in a column this week:

Texas did not gain 1 million jobs in the 2007-2012 period Moore measured. The correct figure was a gain of 497,400 jobs.

Florida did not add hundreds of thousands of jobs in that span. It actually lost 461,500 jobs.

New York, with [its] very high income tax rates, did not lose jobs during that time. It gained 75,900 jobs.

Oops, indeed.

In an email exchange, Pepper says, she presented Abouhalkah’s findings to Moore, and he agreed to a detailed correction, which ran on page 2 of the paper in an edition last week. The Star’s corrected version of the online column, published July 24, can be seen here.

The corrections

Moore’s piece, and the mistakes it included, did not appear only in the Star. When Abouhalkah discovered the errors, Pepper informed editors at the Wichita Eagle, the Star’s sister McClatchy paper, which had also run the piece. The Eagle ran its own correction, somewhat different from the Star’s. The original version published in Investor’s Business Daily remains uncorrected as of this writing. (IBD, which identifies Moore as part of its “brain trust,” did not respond to a request for comment.)

I sent links for all of these versions to Craig Silverman, a former CJR contributor who now writes the Poynter Institute’s Regret the Error blog. “This is a great case study to show the lack of standardization with corrections from one news outlet to another,” he replied.

Deron Lee is CJR's correspondent for Iowa, Missouri, Kansas, and Nebraska. A writer and copy editor who has spent seven years with the National Journal Group, he has also contributed to The Hotline and the Lawrence Journal-World. He lives in the Kansas City area. Follow him on Twitter at @deron_lee.