Received: 16 September 2024 Revised: 16 February 2025 Accepted: 14 March 2025 DOI: 10.1111/1745-9125.12407 RESEARCH NOTE Flawed research on the impact of law reform: The case of legal prostitution and sex trafficking, a research note Ronald Weitzer Department of Sociology, George Washington University, Washington, District of Columbia, USA Correspondence Ronald Weitzer, Department of Sociology, George Washington University, Washington, DC 20052, USA. Email: weitzer@gwu.edu Abstract This research note examines a finding that contradicts previously well-established knowledge in the field of organized crime, as well as studies of the effects of legalizing vice. Unlike research on the aftermath of Prohibition in the United States post-1933, decriminal- ization of casino gambling in Nevada post-1931, and legalization of cannabis, little is known about the effects of legalizing prostitution. Here, I offer a critique of some influential research that purports to find a rela- tionship between legalization of prostitution and an increased magnitude of sex trafficking. After identifying serious flaws in these studies’ conception and execu- tion, I briefly show that their problematic findings have become the conventional wisdom regarding the relation- ship between trafficking and legalized prostitution—as reflected in news reports, legislative debates, Google’s topline assessment, and the outcome of a constitutional challenge to Canada’s current prostitution law. KEYWORDS criminalization, legalization, prostitution, sex trafficking 1 INTRODUCTION Since the 1970s, some countries have legalized prostitution. Australia, Austria, Belgium, Germany, Mexico, the Netherlands, New Zealand, and Switzerland are among these countries. The specific rights and regulations governing sex work are based on federal, state, or municipal laws, which Criminology. 2025;63:557–569. © 2025 American Society of Criminology. 557 wileyonlinelibrary.com/journal/crim