Kennedy claimed that in 1946, he provided information – including secret codewords and details of Klan rituals – to the writers of the "Superman" radio program, intending to strip away the Klan's mystique. There was a series of 16 episodes in which Superman took on the Klan. He claimed that the trivialization of the Klan's rituals and codewords likely had a negative impact on Klan recruiting and membership, leading Stephen J. Dubner and Steven Levitt to dub Kennedy "the greatest single contributor to the weakening of the Ku Klux Klan" in their 2005 book "Freakonomics". However, in 2006, Dubner and Levitt cast doubt on the statements of Kennedy, stating "the story of Stetson Kennedy was one long series of anecdotes -- which, no matter how many times they were cited over the decades, were nearly all generated by the same self-interested source".