Allan Lichtman responds to Nate Silver's criticism of "Keys to the White House" criticism

Allan J. Lichtman, the presidential historian at American University whose “Keys to the White House” system we posted a critique of here last week, has kindly prepared a response. (Mr. Lichtman’s system forecasts that President Obama is a heavy favorite to be re-elected in 2012.)

Mr. Lichtman’s response is reproduced below. My policy is to let authors have their own say in these cases, so any further response I have will be contained in a separate post, with the exception of a brief technical comment at the end.

The Keys Work: A Response to Nate Silver
Allan J. Lichtman

I read with great interest Nate Silver’s analysis in the New York Times blog of my system for predicting presidential election results, The Keys to the White House. His work demonstrates the kind of lively debate that the keys can generate. However, his critique of the keys system cannot withstand scrutiny.

Mr. Silver has either failed to read or simply ignored the detailed discussion of the keys in my book “The Keys to the White House” (5th edition forthcoming from Rowman & Littlefield early next year) or in technical articles that I published in peer reviewed journals (for example, International Journal Of Forecasting (April-June 2008) and International Journal Of Information Systems & Social Change (January-March 2010).

Mr. Silver’s neglect of the published work on the keys system has resulted in fundamental misconceptions about the development and application of the keys that fatally flaw his critique. Mr. Silver presumes that I took 38 elections from 1860 to 2008 with known outcomes, found 13 key factors out of innumerable combinations of factors and used the impermissible methods of “overfitting and data dredging” to force the calls on these keys to conform to the results of these elections. In fact, the book and articles make clear that I followed a very different and scientifically sound procedure designed precisely to avoid the fallacies of “overfitting and data dredging.”...