The National Canine Research Council explains the results of the new study. You can view the full discussion here: http://nationalcanineresearchcouncil.com/dog-news/
For example, in order to prevent a single hospitalization resulting from a dog bite, the authors calculate that a city or town would have to ban more than 100,000 dogs of a targeted breed. To prevent a second hospitalization, double that number. Dog-bite related fatalities are so extremely rare that not even a state could ban enough dogs to insure that they had prevented even one.
You can purchase the complete study from the Journal of the American Veterinary Medical Association: http://avmajournals.avma.org/doi/full/10.2460/javma.237.7.788
Journal of the American Veterinary Medical Association
October 1, 2010, Vol. 237, No. 7, Pages 788-792
Use of a number-needed-to-ban calculation to illustrate limitations of breed-specific legislation in decreasing the risk of dog bite–related injury
Gary J. Patronek, VMD, PhD; Margaret Slater, DVM, PhD; Amy Marder, VMD
Center for Shelter Dogs, Animal Rescue League of Boston. 10 Chandler St, Boston, MA 02116. (Patronek, Marder); American Society for the Prevention of Cruelty to Animals, 1717 S Philo Rd, Ste 36, Urbana, IL 61802. (Slater)
Address correspondence to Dr. Patronek (firstname.lastname@example.org).