there is a lot of different studies and statistics that say that as a breed, pitbulls bite more per capita and they kill MUCH more when they do bite. You can't just say that every study is wrong or misidentified the breed involved. I do believe that happens at times. I also believe that much of the time, owners who want pitbulls also want/encourage aggressive behavior. Even with all that, I think the stats show they are more dangerous than other breeds.

http://www.dogsbite.org/dog-bite-statistics-fatalities-2015.php?gclid=COed3d6GuNICFUK5wAodSHQJJw