Flora-the usual ad hominem attack. Why don't you deal with the long list of objections that Weitzer summarizes instead of attacking the (supposed) views of the author?
I did provide a brief one liner on what was wrong with the original paper (Cho, S. Y., Dreher, A., & Neumayer, E. (2012). Does legalized prostitution increase human trafficking? World Development, 41,67–82) here. I would invite readers to read both the Weitzer and Cho papers.
Another problem with the Cho paper (besides as I mentioned the fact that the trafficking figures are not collected in a uniform way from country to country-include labour trafficking, people smuggling as well as sex trafficking-so CANNOT be Compared) and should have been clear to any decent editor and is illustrated in fig.1 which summarizes the data.
What the figure claims to show is the relationship between trafficking and legalization of prostitution in a number of different countries. It is a scatter plot through which the authors have drawn a gently up-sloping line-which is the claim they are trying to make. If you look at the raw data-it is all over the shop-no competent editor of a scientific journal should have accepted that-its pretty much garbage-as is the rest of the paper. It is all very well trying to cover the scatter in the data with statistics but its always best to look at the raw data instead of the summary tables.
Now it could be that there is a relationship between legalization and trafficking but this paper is not good enough to show that for sure.