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Unethical Behavior: Creating Mary Rosh, A False Online Identity


  • Researcher John Lott’s most consistent and passionate defender against online criticism was a self-described former student of Lott’s named Mary Rosh.
  • In 2003, one of Lott’s colleagues at the CATO Institute compared IP addresses and exposed Rosh as a false identity created by John Lott.
  • Despite admitting that he created Mary Rosh in 2003, Lott testified before Congress in 2019 that his family often used that account to defend him online.  

The Situation:

Lott is known to directly engage with critics online and vigorously defend his work. Between 1999 and 2003, he was aided by his most consistent defender Mary Rosh who identified herself as a former student of Lott at the University of Pennsylvania’s Wharton School. In addition to posting comments on blogs and news articles about Lott’s work, Rosh posted 295 times in Usenet forums, a precursor to internet forums where academics would congregate to discuss their work.

On August 18, 1999, “maryrosh from Philadelphia” posted a rave review of Lott’s book with the subject line, “SAVE YOUR LIFE, READ THIS BOOK — GREAT BUY!!!!” She said that “Unlike other studies, Lott used all the data that was available. He did not pick certain cities to include and others to exclude. No previous study had accounted for even a small fraction of the variables that he accounted for.”

On November 9, 2001, Rosh posted a description online of Lott as “the best professor I ever had” and said “Lott taught me more about analysis than any other professor that I had and I was not alone. There were a group of us students who would try to take any class that he taught. Lott finally had to tell us that it was best for us to try and take classes from other professors more to be exposed to other ways of teaching graduate material.”

Twice in January 2002, Rosh advocated for carrying a gun instead of a knife for self-defense, asking, “As a woman, who weighs 114 lbs, what am I supposed to do if I am confronted by a 200 lb. Man?” The following day she added, “Even if I am not wearing heels, I don’t think that there are many men that I could outrun.”

Rosh defended Lott with precise citations, often mentioning exact page numbers and table references in Lott’s work. On June 2, 2000, Rosh posted online asking  people to download one of Lott’s papers as frequently as possible so it would get noticed by other academics. 

In some of her posts, Rosh takes attacks personally that were directed towards Lott. On July 26, 2001, she replied to a post critical of Lott saying, “This posting is filled with lies. Lott is not a ‘shill’ for anyone. Prove your claim.” On August 5, 2001, a commenter noticed Rosh’s sometimes emotional defenses of Lott and replied, “I’m sorry if you’re taking this personally, but you are not John Lott.”

As it turns out, Mary Rosh actually was John Lott. In 2003, one of Lott’s colleagues at the CATO Institute exposed Rosh as a false identity created by John Lott. Julian Sanchez thought it was strange that Rosh criticized bloggers for posting a link to a debate over a controversial survey of Lott’s without calling Lott first. Sanchez wrote, “This sounded odd, not only because bloggers very seldom do that kind of background research before posting a link, but because Lott had made precisely the same criticism several times in e-mails to bloggers covering the story.” Sanchez compared the IP addresses from Mary Rosh’s forum posts with the IP address in an email that John Lott had sent him and discovered they were identical. 

On January 22, 2003, John Lott admitted he created Mary Rosh and sent an email from MaRyRoSh@aol.com confessing, “The MaRyRoSh pen name account was created years ago for an account for my children, using the first two letters of the names of my four sons. (They later got their own accounts but this one was never erased.) I shouldnt have used it, but I didnt want to get directly involved with my real name because I could not commit large blocks of time to discussions.”

The following month, journalist Michelle Malkin wrote in a TownHall article, “Lott’s invention of Mary Rosh to praise his own research and blast other scholars is beyond creepy. And it shows his extensive willingness to deceive to protect and promote his work.” 

In a June 2003 letter to Science Magazine, Lott wrote, “I used a pseudonym in Internet chat rooms because earlier postings under my own name elicited threatening and obnoxious telephone calls.” In response to Lott’s letter, Donald Kennedy, the editor of Science, wrote, “Lott cannot dismiss his use of a fictitious ally as a ‘pseudonym.’ What he did was to construct a false identity for a scholar, whom he then deployed in repeated support of his positions and in repeated attacks on his opponents. In most circles, this goes down as fraud.” 

The Mary Rosh controversy earned Lott a spot in the 2014 book The Encyclopedia of Liars and Deceivers written by Roelf Bolt and Andy Brown.

Lott’s counter:

On September 18, 2019, Lott was asked about Mary Rosh during his testimony before the U.S. Congressional Joint Economic Committee. Lott said, “Well, it was basically the family email account that we had. Basically based on the names of my four sons at that time. It was an account that the family used.” 

After reading a comment by “Mary Rosh” that said Lott was her best professor, US Sen. Martin Heinrich of New Mexico asked Lott if that showed good judgment. Lott replied, “First of all, I did not write that. It was a family account and there was somebody else in my family who was responding to attacks that were on me, okay? So I don’t police everybody in my family when they go and do things like that and I had members of my family who wrote a couple reviews on my books and other things like that I’m not going to go and tell.” 

Heinrich then said, “You’re quoted in this article as saying ‘I probably shouldn’t have done it.’” Lott replied, “There are two different issues here. Did I use that account myself sometimes? And I did, mainly because when I had originally participated in these internet chat rooms.” Lott was unable to finish his reply because his allotted time expired.


An examination of Mary Rosh’s full history of several hundred comments demonstrates that it could not have been his wife and kids engaging in the arguments over econometrics. 

For example, Rosh wrote the following in an October 12, 2001 comment, “Even dropping out counties with fewer than 100,000 people and all Florida counties, Black and Nagin find a 6.3 percent drop in Assaults (significant at the 1 percent level) and a 4.6 percent drop in robberies (significant at the 6 percent level).”

On August 14, 2002, Rosh wrote, “I don’t see where Lott claimed that the differences were statistically significant at the 95 percent level for a two-tailed t-test. Why isn’t the standard the perponderance [sic] of the data?… The question of significance for that result at the 95 percent level for a two-tailed t-test isn’t even being debated here. Nor is anyone debating whether the point estimates indicate that we women appear to get a great benefit from using a gun than do men. If one is merely asking whether the perponderance [sic] of the evidence indicates that women get a bigger benefit, Lott’s statement is exactly correct.”


Tim Lambert, “Mary Rosh’s blog, “ ScienceBlogs, January 21, 2003
Kevin Drum, “JOHN LOTT EXPLAINS….I got an,” Washington Monthly, January 22, 2003
Michelle Malkin, “The other Lott controversy,” Townhall, February 5, 2003
John Lott, “Research Fraud, Public Policy, and Gun Control,” Science, June 6, 2003
Donald Kennedy, “Response,” Science, June 6, 2003
Roelf Bolt, The Encyclopedia of Liars and Deceivers, 2014
John Lott testimony before the Joint Economic Committee Gun Violence in America, “Gun Violence in America Understanding and Reducing the Costs of Firearm Injuries and Deaths,” YouTube, September 18, 2019
Julian Sanchez, “The Mystery of Mary Rosh,” Reason, May 2003

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