A great new website, Spurious Correlations, has just appeared on my radar, and it fantastically illustrates the Post Hoc fallacy. The website takes data sets, and then hunts through the web to find data sets that correlate with the initial data and then presnts it in the form of a chart. The headline for the post comes from this chart:
As this chart nicely shows, there is a correlation between Nicholas Cage films and drowning deaths in swimming pools. There is clearly no causal relation that I can think of here (though Cage has certainly appeared in some dire films recently), but there is a clear and obvious correlation. This entire website does a great job of illustrating the mantra that "correlation does not equal causation." I encourage everyone to take a look at the site because many of the correlations are interesting and quite humorous.