Steven Levitt’s Freakonomics got a lot of attention, largely for its discussion of the abortion-cut-crime hypothesis (debunked here and here). Fewer people know, however, about gun scholar John Lott’s lawsuit against Levitt.

In the book Levitt claimed that other researchers disproved Lott’s study — finding that concealed carry reduces crime — by failing to replicate it. Lott sued, pointing out that every time a researcher repeated Lott’s methods on Lott’s data, the results were the same.

Lott also argued Levitt’s e-mail to another economist, stating that Lott basically bought an issue of an academic journal to run research he agreed with, was libelous.

The judge ruled against the first allegation. The word “replicate” does have a specific meaning in science: repeating an experiment precisely. However, the book was in large part marketed to the general public, which would take the sentence to mean that other scientists, using different methods and statistics, have come to different conclusions.

In defamation law, there’s a practice of “innocent reading,” that is, if a statement can be taken two ways and one of them is not libelous, the non-libelous one should prevail. What’s interesting here is that there are two audiences; one could read it two ways, but the other could only read it in the libelous way. The judge ruled that the general public’s reading was the one that counted, even though many academics also read the book (it is, after all, an application of econometric methods).

One thing I would like to point out is that, even if Levitt’s statement is read innocently, it’s misleading though not libelous. On his Web site Lott has an extensive collection of research by various authors, published in various journals, that supports his thesis. There are those who disagree, saying that concealed carry does not affect or even increases crime, but Levitt implies there’s a broad consensus that Lott is wrong, and that’s simply not the case. Even James Q. Wilson, writing in a dissent from a National Academies of Science report (the report itself found no difference in either direction), said a wide variety of methods confirmed Lott’s results.

The judge deemed the second allegation “actionable,” meaning not that Lott has won but that, if Lott proves the allegation is true, he will win. As a public figure (one who knowingly entered the previously existing public controversy of gun control), Lott will have to demonstrate actual malice, that Levitt sent the e-mail knowing it was false, or with reckless disregard as to whether it was.

Robert VerBruggen blogs at http://www.therationale.com.