Less Wrong is a community blog devoted to refining the art of
human rationality. Please visit our About page for more
information. Correlation does not imply causation. Sometimes
corr(X,Y) means X=>Y; sometimes it means Y=>X; sometimes it
means W=>X, W=>Y. And sometimes it's an artifact of people's
beliefs about corr(X, Y). With intelligent agents, perceived
causation causes correlation. Volvos are believed by many people
to be safe. Volvo has an excellent record of being concerned
with safety; they introduced 3-point seat belts, crumple zones,
laminated windshields, and safety cages, among other things. But
how would you evaluate the claim that Volvos are safer than
other cars? Presumably, you'd look at the accident rate for
Volvos compared to the accident rate for similar cars driven by
a similar demographic, as reflected, for instance in insurance
rates. (My google-fu did not find accident rates posted on the
internet, but insurance rates don't come out especially pro-
Volvo.) But suppose the results showed