Paul Krugman has weighed in to an ongoing debate sparked by Jonathan Chait’s criticism of a passage in my essay “Keeping America’s Edge.” I believe that I have responded to Mr. Chait’s assertions comprehensively. Unlike Chait, Professor Krugman has argued that I have presented incorrect data.
Krugman says this:
But I went back to Manzi’s source of data, and it turns out that it’s even worse than that. If you use the broad definition of Europe, which includes the USSR, it did indeed have 40 percent of world output in the early 1970s. But that share has not fallen to 25 percent — it’s still above 30 percent.
His assertion is flatly false.
First, Krugman has incorrectly identified my source of data.
I have never corresponded with Krugman concerning data sources and analysis for the passage in question (unlike Chait, who was careful to contact me prior to publishing his blog post, and to whom I sent data sources and calculation details), so I cannot know on what basis Krugman asserts that the dataset to which he links is my “source of data.” It is not. As per the blog post in which I reviewed multiple data sources for the analysis in question, I averaged multiple sources of data. Krugman has selected only one of these sources, presented it as if it were my sole source, and therefore (obviously) failed to replicate the published result. The error is his.
Second, Krugman incorrectly interpreted the economic dataset that he did identify.
According to the dataset in question, that part of Europe excluding any part of the USSR had about 40 percent share of global GDP in 1973 [Cell H59 in the spreadsheet]. According to this dataset, if you add the USSR to this definition [Cell H59 + Cell H102], then such a constructed entity would have had global GDP share of about 44 percent, not the 40 percent that Krugman asserts. Not that such a constructed entity is precisely relevant to the argument anyway: Professor Krugman is also incorrect that my “definition of Europe included the Soviet bloc (!).” I was very careful to try to identify only the economic output of those sub-components of the USSR that were west of the Urals, as per the dictionary definition of Europe. Therefore, the estimate from this dataset for Europe was about 43 percent. Averaged with the other dataset available to me for that year (also cited and linked in my blog post), you will find an estimated global GDP share of 39.8 percent, or as I said in my article, “a little less than 40%.”
Krugman graciously extended me the courtesy of saying that my analysis was “probably not a deliberate case of data falsification,” and instead assumed that I “glanced at some numbers, thought [I] saw [my] assumptions confirmed, and never checked.” I will extend to him the same courtesy.