McDowall's study for the "American Journal of Public Health" contrasted with a 1995 study by Gary Kleck and Marc Gertz, which found that 2.45 million crimes were thwarted each year in the U.S. using guns, and in most cases, the potential victim never fired a shot. The results of the Kleck studies have been cited many times in scholarly and popular media. The methodology of the Kleck and Gertz study has been criticized by some researchers but also defended by gun-control advocate Marvin Wolfgang.