Repeat after me:
We discussed causation and correlation in my Methods class this morning. I generally use the ice cream sales and murder rates example, but since this has been floating around the internet lately, I figured I would throw it in. It got a few chuckles out my class, from those who also wanted to insist that ice cream made people deranged and thus more likely to murder someone, but a good reminder nonetheless. A regression of murder rates on ice cream sales or internet explorer market share will have a positive and statistically significant coefficient estimate, but it doesn’t mean that either is causing more murders to occur.
ERIN K. FLETCHER 