Evaluation of the C-BARQ as a measure of stranger-directed aggression in three common dog breeds

To best understand this article in the context of the Breeds and Behavior literature, please see National Canine Research Council’s complete analysis here.

van den Berg, S. M., Heuven, H. C. M., van den Berg, L., Duffy, D. L., & Serpell, J. A. (2010). Evaluation of the C-BARQ as a measure of stranger-directed aggression in three common dog breeds. Applied Animal Behaviour Science, 124(3-4), 136-141. doi:

National Canine Research Council Summary and Analysis:

This article is included because it evaluates the ability of the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) to quantify the incidence of warning and possibly biting behaviors toward strangers among pet dogs labeled by their owners as either Golden Retrievers, Labrador Retrievers, or German Shepherds.

van den Berg et al. (2010)  propose that Classical Test Theory may not be adequate to analyze the relationship among the questions that have clustered around the trait called stranger directed aggression (SDA) by the authors of the C-BARQ using traditional factor analysis (Hsu & Serpell, 2003). van den Berg et al. (2010), use another kind of statistical analysis, Item Response Theory  to both attempt to confirm the correlations among the relevant 10 items on the C-BARQ and to reveal a more nuanced relationship among the items with regard to the 3 popular breeds whose results they looked at.

Their results showed that German Shepherds have significantly higher SDA than Labradors, and Labradors have higher SDA than Golden Retrievers. However, though German Shepherds had higher scores overall, they had relatively lower scores for one of the scale items: SDA towards mail carriers and delivery persons. Conversely, Golden Retrievers showed more aggression on this item than the other included breeds.

This would be a useful addition if the most serious issues with the C-BARQ related to the factor analysis originally performed. This is, however, not the case. The difficulties with this, as with most extrapolations of owner surveys to the population level, is with the data itself. There is no way to determine the role of the owner’s perceptions with regard to the behaviors reported. This is particularly problematic when the groupings of interest are breeds. Not only may the owners’ breed based expectations bias their perceptions, they may also influence their husbandry decisions: an owner who believes his dog to be a German Shepherd may in effect train his dog to act like the owner’s stereotype of a German Shepherd. To confound matters even further, the instrument includes no mechanism for the owner’s identification of his dog’s breed, meaning that these labels are themselves suspect. The respondents may well not actually be reporting on dogs of the breed they think they are. These pitfalls may be particularly treacherous when considering breeds with strong stereotypes, like the three included in their study. For example, individuals who want a protective dog may choose to purchase a dog they are told is a German Shepherd because of their associations with military and police work, and their stereotype for being guard dogs, whereas a family with young kids may choose a dog labeled a Golden Retriever due to their stereotype of being family-friendly, loyal, and gentle. These biases, whether overt or covert, and warranted or not, can shape how behavior is interpreted, remembered, and reported. No statistical model, regardless of sophistication and robustness, can remedy these biases.

Importantly, the data were transformed to be dichotomous because any occurrence of SDA was very low for all three breeds. The C-BARQ employs a 5-point scale (0-4) with SDA labels indicating “no visible signs of aggression,” “mild aggression,” “moderate aggression,” “more pronounced aggression,” and “serious aggression.”  Because “aggression” is broadly defined within the C-BARQ: “Typical signs of moderate aggression in dogs include barking, growling and baring teeth. More serious aggression generally includes snapping, lunging, biting, or attempting to bite,” this means that increased barking could be the difference in “aggression” as reported by owners. Thus, practical validity is low, at best.

Abstract and Link to Purchase Full Text of the Original Article:

Additional reference:

Hsu, Y., & Serpell, J. A. (2003). Development and validation of a questionnaire for measuring behavior and temperament traits in pet dogs. Journal of the American Veterinary Medical Association, 223(9), 1293-1300.

Page last updated July 16, 2019