Hi Shelley, others, Slate recently had a great article on correlation and causation with a historical perspective.
My favorite line: "'No, correlation does not imply causation, but it sure as hell provides a hint." http://www.slate.com/articles/health_and_science/science/2012/10/correlation_does_not_imply_causation_how_the_internet_fell_in_love_with_a_stats_class_clich_.html "Having nothing better to do, I set fire to the prairie." -- Francis Chadron, 1839, Fort Clark, North Dakota http://www.devanmcgranahan.info
