Megan McArdle smacks down certain people--they know who they are--precisely (4/2):
But I expect that four years from now, we'll still be having the same conversations with proponents of "cancer clusters" and Democrats convinced that they can scientifically prove that Democrats are better for GDP by doing ham-fisted regressions of Democratic presidencies with a few tightly correlated economic variables. What's the mechanism? What makes electric power lines cause cancer, but not the earth's vastly more powerful magnetic field? What policies did Harry Truman and Bill Clinton have in common (but not with Richard Nixon) that caused this marvelous confluence? Well, maybe we don't know the mechanism exactly, but never you mind: just look at that bee-yoo-ti-ful correlation!