Dog Bite-Related Scientific Studies

0

Number of studies that have concluded that any specific breeds are "inherently more dangerous" than other breeds

12

Number of studies (on this page alone) that reject breed-specific legislation as an effective approach for public safety

98%

Percentage of "pitbull-type" dogs that are mixed breed dogs (not purebred) by DNA
​(Study #5)
The scientific consensus on the topic of breed-specific risk is clear - multiple peer-reviewed studies have concluded that a dog's breed does not determine risk and that breed-specific legislation (BSL) is ineffective. The position of the scientific consensus is important because while individual and limited-scope studies can always be found to support opposing viewpoints, the scientific consensus is what the larger scientific community has concluded to be valid based on a comprehensive collection of scientific research. A selection of the studies supporting the scientific consensus on the topic of breed-specific risk, including their summaries and conclusions, is provided below. While there are a number of other studies that have reached similar conclusions about breed-specific risk and BSL, we've only included peer-reviewed studies published by reliable research organizations in order to provide the most accurate information available.

Study #1 - Breed Risk

Summary:
  • Study published in 2013 that analyzed 10-years of dog bite-related incidents with breed-based data.
  • Data includes dog breed-related risk information.
  • The study was conducted by researchers at Tufts University (Center for Animals and Public Policy, Department of Environmental and Population Health, Cummings School of Veterinary Medicine) and published by the American Veterinary Medical Association (AVMA).
  • Source: https://www.ncbi.nlm.nih.gov/pubmed/24299544
Conclusions & Findings:
  • Factors associated with irresponsible ownership are the primary cause of dog bite-related fatalities and breed is not a factor (breed does not determine risk).
  • ​Media reports are a poor source for breed information as there are a high percentage of discrepancies (over 40%) between the breed reported in the media and the subsequent breed identification by animal control; additionally, valid breed determination was only possible in 18% of all incidents.
  • ​The study rejects breed-specific legislation (BSL).

Study #2 - Bite Severity

Summary:
  • Study published in 2017 that analyzed 140 dog bite incidents over a period of several years.
  • Data includes dog bite-related risk information.
  • The study was conducted by researchers at the Creedons College Ireland (Department of Dog Behaviour) and the National University of Ireland (School of Psychology) and published by the Irish Veterinary Journal.
  • Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5521144/
Conclusions & Findings:​
  • There is no difference (in the medical treatment required following a bite or in the type of bite inflicted) between dog bites by breeds stereotyped as "dangerous" (legislated breeds such as German Shepherds, Rottweilers, and "pitbull-type" dogs) and other breeds of similar sizes and strengths that are not stereotyped as "dangerous" (non-legislated breeds such as Boxers, Labrador Retrievers, and Bulldogs).
  • ​Dog bites by breeds not perceived as "dangerous" (non-legislated breeds) are less likely to be reported.
  • ​The study rejects breed-specific legislation (BSL).

Study #3 - Dog Bite-Related Statistics

Summary:
  • Study that analyzed 20 years of dog bite-related fatality incidents with breed-based data.
  • Data includes statistics for dog bite-related fatalities.
  • The study was conducted by the U.S. Centers for Disease Control (CDC) and published by the American Veterinary Medical Association (AVMA).
  • Study source available at: https://www.pitbullinfo.org/statistics.html
Conclusions & Findings:​
  • Over 25 breeds and dog-types were associated with 238 dog bite-related fatalities (DBRFs) over a period of 20 years.
  • The study's data substantiates that the DBRF risk rate for "pitbull-type" dogs is fully in-line with the risk rates of other large or strong breeds. Furthermore, the majority (72%) of DBRFs in the 20 year dataset were attributed to non-pitbull type breeds.
  • ​The study rejects breed-specific legislation (BSL).

Study #4 - Breed identification & DNA

Summary:
  • Study published in 2015 that assessed the breeds of 120 dogs and analyzed breed identification errors.
  • Data includes statistics for breed identification errors between visual breed identification and DNA signatures.
  • The study was conducted by University of Florida (College of Veterinary Medicine), Michigan State University (College of Veterinary Medicine), Jacksonville FL Humane Society, Jacksonville FL Animal Care and Protective Services, Tallahassee FL Animal Services, Marion County Animal Services Ocala FL, and published by the The Veterinary Journal.
  • Source: https://www.sciencedirect.com/science/article/pii/S109002331500310X
Conclusions & Findings:
  • "Pitbull-type" dogs were misidentified 60% of the time (62 were visually identified as "pitbull-type" but only 25 had DNA signatures from any of the pitbull-type breeds). Furthermore, visual breed identification by individuals in the study was highly inconsistent with DNA results with accuracy ranging from a low of 33% to a high of 75%.
  • "Lack of consistency among shelter staff indicated that visual identification of pitbull-type dogs was unreliable."
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes: "Since injuries from dogs have not decreased following bans on particular breeds, public safety is better served by focusing on recognition and mitigation of risk factors for dog bites."

Study #5 - Breed identification & DNA

Summary:
  • Study published in 2018 that tested and analyzed the DNA of 919 dogs from 2 different shelters (in Arizona and California). The DNA results were then compared to the visual identification of the dog's breed by shelter staff.
  • Data includes statistics for breed identification errors between visual breed identification and DNA signatures.
  • The study was conducted by researchers at Arizona State University.
  • Study link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107223/

Conclusions & Findings:
  • 98% of the pitbull-type dogs in the study were identified to be mixed breed dogs by DNA testing. Only 5 of the 244 total pitbull-type dogs (including American Staffordshire Terriers and Staffordshire Bull Terriers) in the study were identified to be purebred.
  • Dogs labeled as a pitbull-type breed had an average DNA concentration of 43.5% from pitbull-type ancestry (38.5% average in shelter 1 and 48.4% average in shelter 2) and the majority (62% or 152 of 244) of pitbull-type dogs in the study had less than a 50% DNA concentration from pitbull-type ancestry.
  • Using appearance to determine breed was once again determined to be highly unreliable with accuracy ranging between 10.4% and 67.7%.
  • ​The study rejects breed-specific legislation (BSL) as it concluded: "Because there is a lack of any scientific basis for judging how breed signatures interact within an individual dog, we believe shelters should instead focus their resources on communicating the morphology and behavior of the dogs in their care to best support matchmaking and adoption efforts."

Study #6 - Breed Aggression

Summary:
  • Study published in 2008 that assessed the differences in aggression between legislated breeds (such as pitbull-type breeds) and non-legislated breeds (other breeds). Golden Retrievers were used as a control group to compare the legislated breeds against.
  • Data includes comprehensive aggression testing results from 415 legislated dogs (such as pitbull-type breeds) and 70 Golden Retrievers (control group).
  • The study was conducted by researchers at the University of Veterinary Medicine of Hanover, Germany and published by the Journal of Veterinary Behavior: Clinical Applications and Research.
  • Source: http://www.sciencedirect.com/science/article/pii/S155878780700264X
Conclusions & Findings:
  • There were no significant differences in aggression between the legislated breed group and the Golden Retriever control group.
  • Specifically, this study concludes: "Comparing the results of golden retrievers and breeds affected by the legislation, no significant difference was found. A scientific basis for breed specific lists does not exist."
  • ​The study rejects breed-specific legislation (BSL).

STUDY #7 - BREED AGGRESSION

Summary:
  • Study published in 2013 that studied canine aggression towards humans.
  • Data includes a comprehensive analysis of multiple risk factors associated with aggression in dogs.
  • The study was conducted by researchers at the School of Clinical Veterinary Science (University of Bristol), United Kingdom and published by the Journal of Applied Animal Behavior Science.
  • Source: https://www.sciencedirect.com/science/article/abs/pii/S016815911300292X
Conclusions & Findings:
  • The study found that aggression is strongly linked to an individual dog's experience and/or environment and that aggression is not a trait that can be associated with any specific breed.
  • The factors associated with increased rates of aggression were not breed-specific and included: un-neutered dogs, the age of the dog, and dogs subjected to punishment-based training methods.
  • Specifically, this study concludes: "It would be inappropriate to make assumptions about an individual animal's risk of aggression to people based on characteristics such as breed."

Study #8 - Bite Strength

Summary:
  • Study published in 2009 that analyzed and measured bite forces in dogs.
  • Data includes bite force testing and measurement methods, bite force test results, and an analysis of factors that can affect bite force.
  • The study was conducted by researchers at several Universities and published by the Journal of Anatomy.
  • Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673787/
Conclusions & Findings:
  • A dog's overall size is the primary significant factor that affects its bite force (not breed).
  • In the study's conclusion, breed was not an identified factor affecting bite force. Specifically, the study concluded: "Force of biting in domestic canids is strongly related to size".

Study #9 - Bite Strength

Summary:
  • Study published in 2018 that analyzed and measured bite forces in dogs and cats.
  • Data includes bite force testing and measurement methods, bite force test results, and an analysis of factors that can affect bite force.
  • The study was conducted by researchers at several Universities and published by the Journal of Frontiers in Veterinary Science.
  • Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5932386/
Conclusions & Findings:
  • A dog's physical characteristics related to size and weight are the primary factors that affect its bite force (not breed).
  • In the study's conclusion, breed was not an identified factor affecting bite force.

Study #10 - Breed-Specific Legislation (BSL) Effectiveness

Summary:
  • Study published in 2013 that assessed differences in dog bite-related incidents between Canadian municipalities with and without Breed Specific Legislation (BSL).
  • Data includes statistics for dog bite incidents in 22 urban Canadian municipalities.
  • The study was conducted by researchers at the University of British Columbia (Animal Welfare Program) and published by the Canadian Veterinary Journal.
  • Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3552590/
Conclusions & Findings:
  • Municipalities that enforced effective breed-neutral regulations such as licensing requirements and ticketing achieved a reduction of dog bite incidents.
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes: "The data provided no evidence of lower dog bite incidence in municipalities with breed-specific legislation."

Study #11- Breed-Specific Legislation (BSL) Effectiveness

Summary:
  • Study published in 2015 that assessed the effectiveness of Breed Specific Legislation (BSL) in Ireland.
  • Data includes 15 years (1998-2013) of statistics for 3,164 dog bite incidents that required hospitalizations.
  • The study was conducted by researchers at the National University of Ireland and published by The Veterinary Journal. Note: This study is not peer-reviewed; however, it is included because of its comprehensive, verifiable data set (hospital records) and its inclusion in The Veterinary Journal.
  • Source: https://www.sciencedirect.com/science/article/pii/S109002331500163X
Conclusions & Findings:
  • Breed-specific legislation is not effective in Ireland and serious dog bite incidents have significantly increased while breed-specific legislation has been enacted.
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes: "The present legislation is not effective as a dog bite mitigation strategy in Ireland and may be contributing to a rise in hospitalizations."

Study #12 - Breed-Specific Legislation (BSL) Effectiveness

Summary:
  • Study published in 2010 that assessed the effectiveness of Breed Specific Legislation (BSL) in the Netherlands.
  • Data includes comprehensive survey results from 1,078 dog bite victims and 6,139 dog owners.
  • The study was conducted by researchers at the Wageningen UR Livestock Research institute (Netherlands) and published by The Veterinary Journal.
  • Source: https://www.sciencedirect.com/science/article/pii/S1090023309003888
Conclusions & Findings:
  • Dog bite incidents are the result of a complex set of factors including dog ownership factors, circumstantial factors, and other factors. Most importantly, the results of breed risk calculations did not match with the breeds legislated by the enacted breed-specific legislation.
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes: "Preventative measures must focus on a better understanding of how to handle dogs." (Breed-neutral approaches)

Study #13 - Breed-Specific Legislation (BSL) Effectiveness

Summary:
  • Study published in 2018 that analyzed the impact of BSL on the number and severity of dog bite-related injuries since BSL went into effect in the city of Odense, Denmark on June 1, 2010.
  • The study used a comprehensive dataset from hospital emergency room records and included records on 2,622 serious dog bite-related injuries from 2002 through 2015 (covering incidents before and after BSL was enacted).
  • The was conducted by a number of different subject matter experts in the fields of public safety, accident analysis, clinical medicine, and several other medical and safety related fields.
  • Source: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0208393​
​Conclusions & Findings:
  • Breed-specific legislation had no effect on dog bite-related injuries.
  • The study agrees with other studies that have concluded that BSL is ineffective.
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes that breed-neutral regulations should be used to reduce dog bite-related incidents.

Study #14 - Breed-Specific Legislation (BSL) Effectiveness

Summary:
  • Study published in 2018 that assessed the effectiveness of Breed Specific Legislation (BSL) in Spain.
  • Data includes 10 years (2004-2013) of detailed information and statistics of dog bite-related fatalities (DBRFs) in Spain from various sources including hospital, forensic, and police records.
  • The study was conducted by researchers at the Sinai Clinic & Research Center (Spain), University of Seville (Spain), Institute of Legal Medicine and Forensic Science (Spain), and published by The Journal of Veterinary Behavior.
  • Source: https://www.sciencedirect.com/science/article/abs/pii/S1558787817301405
Conclusions & Findings:
  • Dog bite-related fatalities (DBRFs) are the result of a number of different factors and breed-specific legislation was ineffective for reducing DBRFs.
  • The study recommends a multidisciplinary, behavior-based approach to further study and address the relevant risk factors associated with DBRFs.
  • ​The study rejects breed-specific legislation (BSL) and specifically concludes: "The implementation of breed-specific legislation in Spain does not seem to have produced a reduction in dog bite–related fatalities over the last decade."

Study #15 - Errors In Medical Studies On Dog Bites

Note about the objective of this study:
​There is a selection of limited-scope medical studies commonly referenced by special-interest groups that support breed-specific legislation (BSL). These disputed studies suggest (but do not substantiate with valid scientific methods or evidence) that bites by "pitbull-type" dogs are more severe than bites by other dogs. To investigate the data and claims made in these studies, a recent peer-reviewed study titled "Defaming Rover: Error-Based Latent Rhetoric in the Medical Literature on Dog Bites" conducted an in-depth qualitative review of these studies and concluded that they contain rhetoric and misinformation including: "clear-cut factual errors, misinterpretations, omissions, emotionally loaded language, and exaggerations based on misunderstood or inaccurate statistics." In other words, these studies are scientifically unsound sources for breed-risk information (as they contain errors and invalid methods) and some were even found to include cherry-picked data to support unscientific conclusions.
Summary:
  • Study published in 2017 that analyzed the characterization and severity of dog bites in medical studies and literature.
  • The study conducted a qualitative content analysis which examined 156 publications identified by terms such as "dog bite" or "dangerous dogs".
  • The study was conducted by researchers at Northeastern University (Boston, MA), Tufts University - Cummings School of Veterinary Medicine (North Grafton, MA), and other subject matter experts.
  • Source: https://www.tandfonline.com/doi/full/10.1080/10888705.2017.1387550
Conclusions & Findings:
  • In many of the medical studies analyzed, there were: "​clear-cut factual errors, misinterpretations, omissions, emotionally loaded language, and exaggerations based on misunderstood or inaccurate statistics."
  • In many of the medical studies analyzed, there was: "misinformation about the significance of breed and breed characteristics."
  • In many of the medical studies analyzed, a due-diligence effort was not performed to accurately and/or scientifically identify the breed(s) involved in the bite incidents included in the studies.
  • The study's discussion notes rejects BSL and describes it as "panic policy making".
If anyone says one dog (breed) is more likely to kill ... that's not based on scientific data.
​​- Dr. Julie Gilchrist, Centers for Disease Control and Prevention