Conversation so far:
how did Steven Levitt get involved with the defamation suit
John Lott filed suit for defamation against Steven Levitt and HarperCollins Publishers over the book Freakonomics and against Levitt over a series of emails to retired economist John B. McCall.
What kind of defamation did John Lott file for against Steven Levitt and HarperCollins Publishers?
In the book Freakonomics, Steven Levitt and coauthor Stephen J. Dubner argued that the results of Lott's research in More Guns, Less Crime had not been replicated by other academics.

Question: Was that true?
Self-contained rewrite: Was that true that In the book Freakonomics, Levitt and coauthor Stephen J. Dubner argued that the results of Lott's research in More Guns, Less Crime had not been replicated by other academics?