Monday, January 26, 2015

Are dog bite convictions really related to ethnicity?

Spider and I have been pondering Auckland SPCA Executive Dirctor Bob Kerridge's reported comments about the link between dog bites and ethnicity. Spider and I have an interest in this: Spider has bitten me (it was my fault) and has been known to be aggressive to strange people when on his leash. Neither of us have been convicted for any of these incidents.

The raw data are that there have been 314 dog attack convictions in Manukau from 2009-2014, and 77 convictions in Auckland City in the sa
me period. Manukau has lots of, you know, ethnic persons, so according to Mr Kerridge it makes sense that "ethnicity does have a bearing factor in terms of dog attacks...those of immigrant [groups] and Pacific Island people...dog ownership is not natural to them." Putting to one side the mangled grammar, the  question arises: is Mr Kerridge right? Is the higher number of convictions for dog attacks in Manukau due to ethnicity?

As anyone who has a slight knowledge of statistics will tell you, what would be a more helpful figure is dog attack convictions per head of population, or per registered dog. If South Auckland has more people and more dogs than Auckland City, then we would expect more dog bite convictions regardless of the ethnicity of the residents. Unfortunately these figures are not supplied.

One thing we do know is that children are more vulnerable to dog attacks than adults, and that there are far more children in South Auckland than in Auckland City. How many of these convictions related to attacks on children? Again, this information is not supplied. We also know that Maori and Pacific people are more likely to be prosecuted and convicted of crime than Europeans. Are conviction rates for dog attacks across Auckland and Manukau comparable?
 
 
And lastly, is the number of convictions the appropriate data by which to judge the dog menace? What about the ACC dog-bite data? What about hospital admission data? Each of these would tell a different story: which is the 'right' story?

Until we know some of this, it is hard to support the claim that the number of dog attack convictions is directly related to the ethnicity of the residents of Manukau. And as for the claim that "dog ownership is not natural to them", that is just spurious nonsense. What's "natural", and how would we know? Surely the point of humans is their ability to learn and adapt.

Mr Kerridge has been a staunch advocate for animals over the years. But perhaps he should leave the statistical comparisons to others.