My previous post presented this:
I’ve now had some time to look at the paper, and here are a few observations:
1. I am of course open to publishing a rebuttal from R&R, but on a first read the authors make a strong case for their claim that the core Reinhart-Rogoff result — concerning the growth slowdown at debt at 90% of gdp — is based on a coding error and some data exclusion issues. Please reread my earlier post on “the smell test.”
2. That said, as Ray Lopez mentions, including in the data the postwar bouncebacks of some Anglo countries (NZ, Australia, and Canada), as recommended by the critics, is not obviously going to improve the quality of the answer. For instance the Kiwis have postwar growth rates of 7.7, 11.9, -9.9, and 10.8 percent, across the late 1940s. Are those numbers — which were combined with high postwar levels of debt — relevant to current fiscal policy issues? I say no, while admitting this may lead us to throw out other data points as well. I don’t know what is the non-cherry-pick answer here or if there even is one.
3. It is perhaps unfortunate in this age of the internet that rebuttals must be presented so quickly, but so be it. It will be interesting to hear from R&R.
4. Not too long ago I reread R&R to ascertain whether they actually present the 90% level as an emergency cliff of sorts. I concluded they did not, although there were some sentences that a reader could take out of context toward confirming such an interpretation.
5. In the paper by the critics, the pp.7-9 discussion of “weighting by country” vs. “weighting by country-year” is very interesting, but the fact that it matters as much as it does makes me more skeptical about the entire enterprise. Whether you should weight by population is important too.
6. I am seeing a large number of tweets which both misrepresent R&R or misrepresent their influence on current policies of “austerity.”
7. My own view, as you can read in The Great Stagnation, is that the primary mechanism is slow growth causing high debt/gdp ratios, not vice versa. In any case this is by far the most important issue, whether or not you agree with my take on it.
8. The “case for austerity” didn’t rest much on R&R in the first place, rather on the notion that the bills have to be paid, dawdling on adjustment is not always so easy, and the feasible sum of international redistribution is quite low. For this reason the UK should be relatively uninterested in immediate austerity and many nations in the eurozone periphery more interested.
9. In the blogosphere, the ratio of blog posts “attacking austerity” to “proposing constructive alternatives to austerity” is at least ten to one. That too tells you something. Many of the alternatives proposed would indeed pass a Benthamite cost-benefit test, at least if implemented as desired, but they are simply inconsistent with incentives and the relatively selfish nature of individual behavior.
10. The most interesting question to me is a rather squirrelly and subjective one: how should this episode change the relative ratios of what I read? Should I in fact read fewer quantitative economics papers, instead (at the margin, of course) preferring more narrative history? This is not the first time that an extremely influential major empirical result has been overturned or at least thrown into serious doubt.