The term “numbers needed to ban” (NNB) is coined to describe this statistical parameter. In the paper, the authors calculate several outcome scenarios based on statistics available from data published in the dog bite literature, such as emergency department visits due to dog bite injury, reconstructive surgery following a dog bite, and frequency of hospitalizations because of a dog bite injury. For all calculations result showed that the numbers needed to ban, based on a particular set of assumptions, were extremely high, therefore, indicating impracticality and implausibility of BSL.
In this writer’s opinion, the argument presented in this paper, using this kind of statistical analysis, is compelling. Nevertheless, the impact the science reported in this paper might have on an emotive real-world problem like dog bite frequency is dubious because of what the authors identify as a “perceptual gap” – that is, the gap between (a) what scientifically is correct and (b) what people believe due to their own biases and belief structures.
The authors believe this gap exists in part because of the widespread fear people have of certain types of dogs, created largely through the dissemination of misinformation about dogs and through highly publicized events in which people are severely attacked or killed by a dog.

 People feel the need to immediately control the problem, hence the knee-jerk reaction favoring the implementation of BSL. The authors conclude that BSL is based largely on fear, and that animal care professionals need to enlighten the public and policy makers about the widespread faulty beliefs that exist concerning the behavioral nature of certain breeds, and about the lack of effectiveness of breed-specific legislation in curtailing the dog bite problem. Expert Breed Specific Legislation

There is a growing awareness that BSL does not improve community safety and penalizes responsible dog owners and their family companions. From January 2012-May 2014, more than seven times as many American communities have either considered and rejected a breed-specific ordinance, or repealed an existing one, as have enacted BSL.[9] Massachusetts, Nevada, Connecticut, Rhode Island, South Dakota, and Utah have recently enacted state laws that prohibit their towns and counties from regulating dogs on the basis of breed. Eighteen states now prohibit BSL. The White House Administration has announced its opposition to BSL, stating that “research shows that bans on certain types of dogs are largely ineffective and often a waste of public resources.”[10]

- See more at: http://nationalcanineresearchcouncil.com/dog-legislation/breed-specific-legislation-bsl-faq/#sthash.VC2tNE0z.dpuf