Dr. Ian Dunbar's bite assessment criteria when assessing a dog bite.
1.. Level 1- Dog growls, lunges, snarls-no teeth touch skin. Mostly intimidation behavior.
2.. Level 2- Teeth touch skin but no puncture. May have red mark/minor bruise from dog's head or snout, may have minor scratches from paws/nails. Minor surface abrasions acceptable.
3.. Level 3- Punctures ½ the length of a canine tooth, one to four holes, single bite.No tearing or slashes.Victim not shaken side to side. Bruising.
4.. Level 4- One to four holes from a single bite, one hole deeper than ½ the length of a canine tooth, typically contact/punctures from more than canines only. Black bruising, tears and/or slashing wounds. Dog clamped down and shook or slashed victim.
5.. Level 5- Multiple bites at Level 4 or above. A concerted, repeated attack.
6.. Level 6- Any bite resulting in death of a human.