I’m on “bloggingheads again”:http://bloggingheads.tv/video.php?id=171 with Dan Drezner. Dan and I had a long discussion about Krugman and whether or not academics should get engaged in broader political debates, dipping into Krugman’s recent “piece”:http://www.rollingstone.com/politics/story/12699486/paul_krugman_on_the_great_wealth_transfer/print on inequality as we went along. One of the things I mentioned was the bit in Krugman’s _Peddling Prosperity_ where he talks about the way in which people can cherry-pick economic statistics in order to prove what they want to prove. Krugman is talking about aggregate growth statistics, but nonetheless the point travels.
by choosing your years carefully and talking a good game, you can seem to prove whatever conclusion you like … We learn that a clever propagandist, right or left, can always find a way to present the data on economic growth that seems to support her case. And we therefore also learn to take any statistical analysis from a strongly political source with handfuls of salt. Someone once said about partisan analysis that they use economic data the way a drunkard uses a lamppost: for support rather than illumination (Peddling Prosperity pp.110-111).
Cue “Alan Reynolds”:http://economistsview.typepad.com/economistsview/2006/12/reynolds_rap_on.html in comments at Mark Thoma’s place, defending a rather dubious-sounding WSJ “editorial”:http://users1.wsj.com/lmda/do/checkLogin?mg=wsj-users1&url=http%3A%2F%2Fonline.wsj.com%2Farticle%2FSB116607104815649971-search.html attacking claims that income inequality has been growing since _1980._
there is no clear evidence of a sustained and significant increase in inequality since 1988 by any other measure. I very carefully did not say there was no such evidence about 1981-87.
Indeed.
Reynolds goes on to defend his choice of periodization, but it would appear that he has a bit of a “track record”:http://delong.typepad.com/sdj/2006/12/intellectual_ga.html#comment-26687832 (to extend Krugman’s metaphor) for employing lampposts not only to provide support, but to meet those other needs and imperatives that drunks are subject to while weaving their way home after a convivial evening.
(Note by the way that Krugman’s criticisms come in the midst of a longer discussion of how chancers at think tanks rather than proper economists have come to dominate debate; while academic peer review doesn’t serve as a perfect protection against this sort of cherry picking, it does make it considerably more difficult to get away with).