I find these blatant "this breed is the most aggressive" statements VERY hard to swallow.

Because of Ivy's reactivity, I've become all too familiar with aggression, arousal, and reactivity problems, and this is my take:

All dogs have some type of aggression. Aggression is a highly aroused state of mind, a step past a dog's normal threshold of tolerance, if you will. If you take a happy Lab who has never growled at anyone, but confine it and taunt it, it will probably bite. In a normal situation, it probably would choose flight and close its eyes or "shut down" into a state of helplessness, where the dog simply hunkers down and mentally shuts down. But take away the ability of flight, add increasing stress, and the dog will show 'aggression'.

ALL dogs have thresholds of tolerance. Some dogs, such as Greyhounds, tend to be very very calm and tolerant. They tend to choose flight before fight. They can tolerate pokes and prods. They can be in high-stress situations and do absolutely fine. But that is their norrmal threshold. Again, if you push them past their threshold (whatever that may be), they could and probably would bite. Giselle, for example, is a certified therapy dog has never growled at a fly. But if she is sleeping and you crouch over her and poke her, she would growl and probably snap at you. Can we fairly call that aggression or an invasion of her threshold? Aggression is a matter of the individual dog and the individual dog's mental state.

It should not be a list of most or least aggressive. Rather, the study should have focused on dogs' high or low tolerances and their susceptibility to overarousal.

Furthermore, there must be a distinction made between aggression and reactivity. Ivy was a regular dog park goer and never had any problems. Yet, whenever she was on leash, she would go bonkers whenever she saw another dog on the streets - lunging, growling, and, yes, she would attempt to hurt them. How can that be? How can she be fine at an off-leash park and an absolute monster on-leash? Aggression is not a black and white thing. It cannot be statistically gauged, IMO. A better factor to gauge would be a dog's arousal and threshold limits.