May 09, 2013

Since when can a mistake in a paper be used as evidence of an opposite conclusion?

Sir, Robin Harding reports “Reinhart and Rogoff publish errata to paper on public debt and growth”. May 9. In it Harding writes that the 2010 paper on public debt and growth, by pointing out a significant effect on growth when public debt reached 90 percent of GDP, was widely cited as an argument for fiscal austerity. Since the paper was thought to be correct, I guess that was a quite reasonable thing to do.

What I cannot lay my hands around though is how the existence of a mistake in the paper can suddenly be turned into evidence which supports the opposite conclusion. I say this because I have lately read more opinions advancing that the 90 percent is no limit, than what I ever read about the original paper stating it was.

That said, since all this type of debt-sustainability discussions often sound to me like a torturer debating how much torture his victim can take before fainting… I will, without any religious fervor invested in it, keep on opining that public debt at 90 percent of GDP is high… although that will of course also have to do with who are the holders of that debt, nationals or foreigners, friends or foes.

And also, if the 90 percent to GDP has been reached by incurring in distortions, like requiring banks to have more capital when lending to the citizens than when lending to the government, then my previous “high” becomes a “VERY HIGH”