I have not seen much evidence used in the debate about breed-specific legislation, most of what I have seen has been opinion ("expert" or otherwise). A recent article from Canada looked at rates of dog bite injury hospitalizations (i.e. serious injuries only, not all bites) and found a small decrease in the hospitalization rate in communities that enacted legislation banning specific breeds.
They pulled out 4 communities to do comparisons - 2 cities, one with breed-specific legislation and one without, and 2 northern towns. I found it interesting that the two communities that did not enact legislation, already had lower bite rates than the communities that did. Where I live, the legislation relates to "dangerous dogs" rather than to specific breeds, so requires some evidence of danger before individual dogs are banned.
The article also references a reason for the targeting of pit-bull type dogs - their stronger bite leading to more serious injuries when they bite, rather than the actual bite rate per breed.
Has anyone else seen this article? Other similar research? I'm curious how often evidence is used in making these decisions, as opposed to rhetoric and hyperbole.