High levels of government debt and the adverse effect this has on the economy has been a key influencing factor in the fiscal consolidation efforts across the world. A key factor providing evidence in support of the connection between high government debts and low economic growth was a paper by two Harvard economists. However, the data used in their research has been called into question.
As we saw in a previous post, It could be you, Carmen Reinhart and Kenneth Rogoff presented a paper back in January 2010. Their research suggested that when a country’s debt increases above 90% of GDP, economic growth will slow considerably. (Click here for a PowerPoint of the above chart.) As you might expect, given the timing of this research, policymakers were intrigued. For those governments in favour of cuts in government spending and increases in taxation to bring the government debt down, this research was dynamite. It seemed to provide the evidence needed to confirm that if left to grow, government debt will have a significantly adverse effect on growth. Here was evidence in favour of austerity.
But, did a simple error create misleading information? A student at the University of Massachusetts Amherst was trying to replicate the results found by Reinhart and Rogoff, but was unable to do so. Thomas Herndon contacted the Harvard professors and they sent him the spreadsheets they had used in their calculations. Looking through it, an error in calculating the average GDP was spotted. However, the student and his supervisors also engaged in further research and came across other inconsistencies. This led to a draft working paper being published in April. The paper did find the same correlation between high debt levels and low growth, but the outstanding results found by Reinhart and Rogoff disappeared. Responding to the error, the Harvard professors said:
We are grateful to Herndon et al. for the careful attention to our original Growth in a Time of Debt AER paper and for pointing out an important correction to Figure 2 of that paper. It is sobering that such an error slipped into one of our papers despite our best efforts to be consistently careful. We will redouble our efforts to avoid such errors in the future. We do not, however, believe this regrettable slip affects in any significant way the central message of the paper or that in our subsequent work.
So, how might this correction and the implications affect government policy? Are we likely to see a reversal in austerity measures? Only time will tell.
Seminal economic paper on debt draws criticism Wall Street Journal, Brenda Cronin (16/4/13)
Reinhart, Rogoff … and Herndon: The student who caught out the Profs BBC News, Ruth Alexander (20/4/13)
Reinhart and Rogoff publish formal correction Financial Times, Robin Harding (8/5/13)
The 90% question The Economist (20/4/13)
Reinhart and Rogoff correct austerity research error BBC News (9/5/13)
Harvard’s Reinhart and Rogoff publish formal collection CNBC, Robin Harding (9/5/13)
Rogoff and Reinhart should show some remorse and reconsider austerity The Guardian, Heidi Moore (26/4/13)
The buck does not stop with Reinhart and Rogoff Financial Times, Lawrence Summers (5/5/13)
Meet Carmen Reinhart and Kenneth Rogoff, the Harvard professors who thought they had austerity licked – and Thomas Herndon, the student who proved them wrong Independent, Tim Walker (22/4/13)
Growth in a time of debt American Economic Review (May 2010)
Does high public debt consistently stifle economic growth? A critique of Reinhart and Rogoff Political Economy Research Institute, Herndon, Ash and Pollin (April 2013)