Re:An Update on Last Week’s Accident
by credit_guy on Saturday March 31, 2018 @09:54AM
(#16723284)
In case anyone's wondering, here's a simple example of 3 variables so that the first is positively correlated with the second, the second positively correlated with the third, but the first and the third have a negative correlation: simply take 3 independent standard normal variables, X, Y, Z, and define our 3 variables to be u=X+Y, v=Y+Z, w=Z-X. Then correl(u,v)=0.5, correl(v,w)=0.5 and correl(u,w)=-0.5.
According to insurance adjusters, age correlates with lower accident rates.
Lower accident rates, or a lower percentage of injury or fatal accidents? I find it hard to believe 80 year olds are getting into fewer accidents than 40 year olds unless it’s because they drive less frequently.
Which would be fine for an insurer of course. Heck, even if they got into more incidents, but the incidents were cheaper, that would be fine for an insurer too.
And not all markets are equally competitive. Just because insurance rates differ doesn't mean risks necessarily do the same way. And let's not forget that while insurers are professional risk assessors that doesn't mean they're infallible either, or immune to other distortions (e.g. pass-the-buck subprime mortgage kind of issues).
And having a hotmail emailaddress with higher accident rates.
I agree with your general point, but you can't just join up 2 correlations like that, that isn't always going to work when there are other confounding factors (and there always are). Wealth also correlates with age which anticorrelates with reaction times and general fitness.