I think I finally found it (Michigan study, 2012). I see why you didn't provide the link...it doesn't support your argument. Here is the final paragraph, "The lack of empirical evidence for the recidivism-reducing beneﬁts of registration and notiﬁcation has not stopped policy makers from imposing additional restrictions on convicted sex offenders. Registration and notiﬁcation laws are now, in some sense, old technology. Today, states are in the midst of imposing even more intrusive laws, such as residency restrictions and civil commitment, with fresh hope of reducing recidivism. These policies may impose even higher costs on sex offenders and their families than registration and notiﬁcation laws have, and research is needed to understand if the effects, if any, of these policies on criminal behavior makes these investments worthwhile." For those wanting to read the entire study, http://repository.law.umich.edu/cgi/viewcontent.cgi?article=1078&context=articles