Krugman Accused of ‘Uncivil Behavior’

May 26, 2013, 6:29 PM

The Wall Street Journal

The gloves are off in the roiling academic dispute over the merits of austerity and the dangers of debt.

In the latest round, Harvard economists Kenneth Rogoff and Carmen Reinhart accused Princeton economist and New York Times columnist Paul Krugman of “spectacularly uncivil behavior” and the inaccurate allegation that they refused to share data supporting their work linking heavy debt levels to subsequent slow economic growth.

Papers such as Mr. Rogoff and Ms. Reinhart’s, which warn of the perils of too much government debt, “haven’t just lost their canonized status, they’ve become the objects of much ridicule,” Mr. Krugman wrote in a recent New York Review of Books attack on advocates of austerity.

“Despite their paper’s influence, Reinhart and Rogoff had not made their data widely available—and researchers working with seemingly comparable data hadn’t been able to reproduce their results,” Mr. Krugman wrote.

Mr. Rogoff and Ms. Reinhart responded Sunday in a five-page letter and a four-page appendix to Mr. Krugman, posted on their website:

“We admire your past scholarly work, which influences us to this day. So it has been with deep disappointment that we have experienced your spectacularly uncivil behavior the past few weeks,” the letter said. “You have attacked us in very personal terms, virtually nonstop, in your New York Times column and blog posts. Now you have doubled down in the New York Review of Books, adding the accusation we didn’t share our data.”

The data in question were used in a body of research by Mr. Rogoff and Ms. Reinhart, including their seminal 2010 paper, “Growth in a Time of Debt.” That paper concluded that during the post-World War II era, levels of public debt above 90% of a country’s gross domestic product generally translate into years of slow growth.

The data used to support their thesis included country figures on real gross domestic product, as well as debt to GDP. The 2010 paper—along with other works by Mr. Rogoff and Mr. Reinhart—were cited by austerity advocates as a justification for ratcheting back public spending after the financial crisis.

The findings came under a cloud last month. Thomas Herndon, a graduate student at the University of Massachusetts Amherst, found a spreadsheet error in the Rogoff-Reinhart calculations in attempting to replicate the paper for an econometrics homework exercise. Mr. Herndon published his findings with two UMass Amherst professors, Robert Pollin and Michael Ash.

Mr. Rogoff and Ms. Reinhart conceded the spreadsheet error but stood by their findings. Early this month, they published on their website a correction to the 2010 paper.

The challenge to a bedrock of post-crisis austerity policy-making had an immediate and global effect. The Rogoff-Reinhart research had made a strong argument for promptly cutting government spending and chipping away at deficits. Mr. Krugman has long attacked this line of thought, warning that curbing government spending now is likely to hinder the economic recovery.

The UMass Amherst paper sparked a world-wide rethink of austerity policies. In recent weeks, Mr. Rogoff and Mr. Reinhart have found themselves squaring off not just with a 28-year-old doctoral student, but also with a Nobel Prize winner in Mr. Krugman.

“Not surprisingly, Reinhart and Rogoff have tried to defend their work; but their responses have been weak at best, evasive at worst,” Mr. Krugman wrote in the New York Review of Books. “Notably, they continue to write in a way that suggests, without stating outright, that debt at 90% of GDP is some kind of threshold at which bad things happen.”

Mr. Rogoff and Ms. Reinhart in their letter told Mr. Krugman, “Your characterization of our work and our policy impact is selective and shallow. It is deeply misleading about where we stand on the issues.”

They also wrote that the UMass Amherst paper “reinforces our core result that high levels of debt are associated with lower growth.” And they said “the accusation in the New York Review of Books” that they had failed to share their data earlier is “a sloppy neglect on your part to check the facts before charging us with a serious academic ethical infraction” and “an unfounded attack on our academic and personal integrity.” The debt and GDP data, they said, have been available on their website since 2010.

Mr. Herndon’s recollection meshes in part with that of Mr. Rogoff and Ms. Reinhart. On Sunday, he recalled accessing debt and GDP data for his replication exercise either directly from the authors’ website or from links on the site. However, Mr. Herndon—who began his attempt to replicate the Rogoff-Reinhart findings in the fall of 2012—noted that he didn’t receive the authors’ spreadsheet—a key piece of his replication exercise and one that revealed the Excel glitch—until early last month. In short, he found some of the data on their web site, but not enough to complete a full replication.

The public challenge to the authors has raised “important issues…over the past few weeks,” for economists, said Justin Wolfers, of the University of Michigan. The dispute, which rippled across the Internet over the weekend, has underscored “the importance of replication in economics,” he said.

On Sunday, Mr. Krugman responded with two posts, including one titled “Reinhart and Rogoff Are Not Happy.”

“This could go on forever, and both they and I have other things to do,” he wrote, adding that he thinks Rogoff and Reinhart have some explaining to do about the relationship between the 90% threshold and growth.

There is “an enormous difference between the statement ‘countries with debt over 90% of GDP tend to have slower growth than countries with debt below 90% of GDP’ and the statement ‘growth drops off sharply when debt exceeds 90% of GDP’. The former statement is true; the latter isn’t. Yet R&R have repeatedly blurred that distinction,” he wrote.