When Policy Meets Statistics: The Reinhart and Rogoff Study on Excessive Debt
Knowing how many of us economists toil away in obscurity on most research, I’m always intrigued by what catches the press’s and public’s attention. Take, for example, the significant attention paid to a 2010 study by Harvard economists Carmen Reinhart and Kenneth Rogoff that concluded that countries with debt levels above 90 percent of GDP began showing slower rates of growth. When Thomas Herndon, Michael Ash and Robert Pollin, scholars at the University of Massachusetts at Amherst, recently had trouble replicating Reinhart and Rogoff’s results, the debate played out in national news outlet.
Unfortunately, this discussion quickly devolved from substance to politics to arguments ad hominem. Without getting into the extent to which I or others can validate Reinhart and Rogoff’s (R&R’s) original findings, I offer six cautions for anyone witnessing this or a similar statistical debate with significant policy implications. Continue reading