Some have argued that the most visible effect of the Swedish law, according to the data presented, seemed to be that since the law came into effect, fewer men reported purchasing sex and prostitutes were less visible. However, the data on men reporting purchasing sex has been called into question for a number of reasons. Firstly, multiple researchers have questioned the influence of legislative change, and the shift from a non-criminal to criminal act being the subject of the question. When any behaviour or act is criminalised there is generally much less self-reporting of it, especially when the interview is not anonymised (as was the case in the data here). Secondly, the most frequently cited data on the decrease in reported purchase of sex by men in Sweden is a question based on lifetime purchases of sex. Given how closely the two surveys were conducted (less than a decade apart), it was found to be statistically impossible for the number to drop so significantly. That is, people can't reverse back to a state of never having bought sex when so many had, just a few years earlier prior to the act becoming criminalised.