An economics paper claiming that high levels of national debt led to low or negative economic growth could turn out to be deeply flawed as a result of, among other things, an incorrect formula in an Excel spreadsheet. The paper has been cited abundantly by the world’s press politicians, including one-time vice president nominee Paul Ryan (R-WI).
The paper, Growth in a Time of Debt, was written by economists Carmen Reinhart and Kenneth Rogoff and published in 2010. The link it draws between high levels of debt and negative average economic growth has been used by right-leaning politicians to justify austerity budgets: slashing government expenditure and reducing budget deficits in a bid to curtail the growth of debt.
This link was always controversial, with many economists proposing that the correlation between high debt and low growth was just as likely to have a causal link in the other direction to that proposed by Reinhart and Rogoff: it’s not that high debt causes low growth, but rather that low growth leads to high debt.
However, the underlying numbers and the existence of the correlation was broadly accepted, due in part to Reinhart and Rogoff’s paper not including the source data they used to draw their inferences.
A new paper, however, suggests that the data itself is in error.
They didn’t average all the rows in their spreadsheet, and they did some fiddly stuff with other data.
Recalculating the data to remove these three issues turns out to provide much weaker evidence for austerity. Although growth is higher in countries with a debt ratio of less than 30 percent (averaging 4.2 percent), there’s no point at which it falls off a cliff and inevitably turns negative. For countries with a debt of between 30 and 60 percent, average growth was 3.1 percent, between 60 and 90 it was 3.2 percent, and above 90 percent it was 2.2 percent. Lower than the low debt growth, but far from the -0.1 percent growth the original paper claimed.