The spread of “Correlation does not imply causation”
Daniel Engber's short article at Slate on the success of the misleading formula "correlation does not imply causation" is doubly relevant here: as an example of the epidemiology of a scientific idea, and as a corrective to a cliché all too common in the social sciences:
"So how did a stats-class admonition become so misused and so widespread? What made this simple caveat—a warning not to fall too hard for correlation coefficients—into a coup de grace for second-rate debates? A survey shows the slogan to be a computer-age phenomenon, one that spread through print culture starting in the 1960s and then redoubled its frequency with the advent of the Internet."