… the actions of economists today bear on the life chances of the world’s population far more substantially than do the actions of the members of most other professions.

George DeMartino

Replication is an activity that doesn’t attract enough attention, enough credit, or enough effort in the social sciences. But it is an activity that is getting a lot of attention at this precise moment. This has come courtesy of the exposure of both flaws and contestable methodological choices in Reinhart and Rogoff’s landmark study of public debt and economic growth.

The economic blogosphere has exploded with debate over the issue. But, just in case you’re not following it, here are the key points. Reinhart and Rogoff followed up their major historical work looking at debt and economic growth This time is different with a paper called Growth in a time of debt published in the American Economic Review in 2010. Their key result is that levels of public debt in excess of 90% of GDP are associated with lower rates of economic growth. Indeed, the mean annual growth rate they report, once debt crosses the 90% threshold, is negative.

This body of work is highly influential.

A quick search on Google Scholar will tell you that the NBER version of Growth in a time of debt has been cited 450 times, while This time is different has been cited over 2000 times since 2009. That is a lot of citations for social science publications: you’re doing pretty well once citations for a piece get into double figures within four years.

In a paper published this week, Thomas Herndon, Michael Ash, and Robert Pollin (HAP) of the University of Massachusetts, Amherst identify problems with the Reinhart and Rogoff result. Continue Reading →