Dog Bite Statistics: Science or Junk Science?
The "Science" of Dog Attacks
There are many studies and data related to dog bites and dog attacks. However, dog attacks on humans occur in the course of complex interactions between two sentient beings and occur in the most uncontrolled and unscientific settings, involving dozens of variables and circumstances which cannot be measured accurately.
For these reasons, there is no “science” behind any of the studies conducted on cases of dog attacks. However, dog attacks can be studied empirically, or through practical observation; and while numbers can be applied to these observations; the numbers have serious limitations and cannot possibly presume to explain the myriad of physical, mental, and environmental factors which occurred prior to a dog attack.
The NCRC data are derived from a statistically insignificant, and very specific, percentage of dogs (i.e., dogs involved in fatal attacks). Therefore, NCRC data is only useful in examining the circumstances surrounding these specific cases and are NOT predictive of the behaviors of any of the 70+ million dogs currently residing in the
There are a number of other studies presently being cited as "science" or as “evidence” of certain canine behavior. Some of these studies were serious, but flawed, attempts by professionals to examine the characteristics of dogs involved in attacks, while other “studies” are merely a haphazard collection of newspaper articles presented as “statistics.”
An examination of the most popularly quoted dog-bite studies is presented:
Junk "Science" - Merritt Clifton's (Animal People)
Mr. Clifton's "study" can be found on a prominent dog-bite attorney website and is being used as "statistical evidence" of breed behaviors by those who seem unable or unwilling to recognize the critical errors in data collection and the damaging and erroneous conclusions drawn from a biased and flawed sample.
An Analysis of Merritt Clifton (Animal People)
Dog Attack Deaths and
Merritt Clifton’s scrapbook of newspaper articles is presented, and often accepted, as an unbiased and accurate representation of dog attacks in the
However, Mr. Clifton arbitrarily excluded dog attacks in which the breed of dog was not “identifiable,” that is, where no one at the scene, or later, claimed to know what kind of dogs were involved. Also excluded were dogs deemed to be used for guarding, police work or as fighting dogs. The uncertainty of any alleged breed identification aside, the exclusion of all attacks by dogs where no breed identification was asserted, combined with the exclusion of dogs used for a specific function, leaves us a list that is utterly unrepresentative of “dog attacks and maimings” in the U.S. and Canada.
Mr. Clifton’s “study” further suffers from the use of a biased sample. There is no national organization in the
Newspaper articles as a biased sample:
Fatal Dog Attack Numbers:
Merritt Clifton located 264 fatal dog attacks in the
The Centers for Disease Control and the National Canine Research Council have documented 477 fatal dog attacks in the
“Maiming” Numbers:
Merritt Clifton located 2,209 “attacks doing bodily harm” occurring between 1982 and 2006 from newspaper articles.
According to the Centers for Disease Control and the National Center for Injury Prevention and Control over 300,000 people report annually to emergency rooms for treatment of dog bites, of whom approximately 6,000 are injured severely enough to require hospitalization.
Hospital admission for injuries sustained during a dog attack is a valid medical assessment of “bodily harm.” Therefore, according to the CDC and the NCIPC, at least 150,000 people received bodily harm (i.e., hospital admission with a median stay of 3.6 days) from dog attacks during the same time period as Clifton's "study." (1982-2006)
Merritt Clifton’s collection of the 2,209 attacks reported in the newspapers is clear evidence that most “attacks doing bodily harm” are NOT reported.
What method editors and reporters use to determine which dog attacks to publicize is unknown.
Clifton then went on to draw sweeping and totally inaccurate conclusions about breed behaviors; presenting his collection of newspaper articles as "evidence" and "predictive" of the nature and behavior of all the other dogs in the U.S.
Pseudo-Science: The CDC Study
The CDC study has been quoted, misquoted, cited, misread, and misunderstood on a regular basis by politicians, the public, attorneys, and the media. Few people actually bother to read the report in its entirety or are willing to acknowledge the severe limitations and flawed methodology used to gather the data which was presented in this study.
An Analysis of the CDC Study
Breeds of Dogs Involved in Fatal Human Attacks in the U.S. between 1979 and 1998
The critical flaw in the CDC's study was the attempt to isolate a factor (breed) which could not be isolated and was impossible to verify.
Of all the more tangible circumstances surrounding a dog attack (sex of dog, reproductive status of dog, location of dog, relationship of dog to victim), the CDC chose, for unknown reasons, the most problematic and least reliable aspect on which to base their study.
Without any legitimate way to identify or verify breeds of dogs, and while knowing that mixed breed dogs make up a significant portion of dogs in the U.S.; the CDC, nevertheless, sought out and attempted to acquire breed information. Since there was, and still is, no national recording system that keeps track of the events surrounding dogs bites, the CDC scanned newspaper articles for breed identifications in cases of fatal dog attacks.
In addition to using newspaper articles, the CDC excluded nearly 1/4 of the small sample population (n=320) due to the fact their source (i.e., newspapers) either failed to report the incident altogether or reported the incident but failed to "identify" a breed.
However, unlike the Clifton study listed above, the CDC recognized the flaws in their study and clearly stated that no conclusions on breed behaviors could be drawn from their data.
The CDC no longer keeps track of dog bite fatalities by breed and has posted the following statement on their website:
"A CDC study on fatal dog bites lists the breeds involved in fatal attacks over 20 years (Breeds of dogs involved in fatal human attacks in the United States between 1979 and 1998). It does not identify specific breeds that are most likely to bite or kill, and thus is not appropriate for policy-making decisions related to the topic. Each year, 4.7 million Americans are bitten by dogs. These bites result in approximately 16 fatalities; about 0.0002 percent of the total number of people bitten. These relatively few fatalities offer the only available information about breeds involved in dog bites. There is currently no accurate way to identify the number of dogs of a particular breed, and consequently no measure to determine which breeds are more likely to bite or kill."
http://www.cdc.gov/ncipc/duip/biteprevention.htm
** The American Veterinary Medical Association (AVMA) released statement on the erroneous use and conclusions of the CDC study:
National Canine Research Council