I heard a rule of thumb that I thought was interesting:
long nose - fast running dog
short nose - slow running dog
So in theory you could decide whether to stop and confront a dog based on the type of dog. Many dogs you just won't beat because they run too fast, the stop and confront is probably better and getting thrown off your bike. Dog that don't run that fast you might get rid of easily....
Any confirmation of that somewhat dubious theory?