Beware Spurious Correlations

spurious correlations


Tyler Vigen manages a humorous website entitled Spurious Correlations. He mines research data from datasets, finds data with similar trends, and creates a chart graphing that data. The result is a “spurious correlation”.  The charts do not imply causation, but rather they are an entertaining visualization of statistics and data manipulation.

Examples of his spurious correlations include:

  • number of people who drowned by falling into a pool correlates with films Nicholas Cage appeared in
  • per capita cheese consumption correlates with number of people who died by becoming entangled in their bedsheets
  • divorce rate in Maine correlates with per capita consumption of margarine
  •  and, the one pictured above, letters in winning word of Scripps National Spelling Bee correlates with number of people killed by venomous spiders

Spurious Correlations makes a serious point behind the amusing posts. Researchers and consumers both need to be critical about what data actually represents. Does A really cause B? Their are a multitude of companies trying to sell an array of consumer products, medications, or supplements that are hoping consumers see causation that just doesn’t exist.

While Vigen is not a statistician, he has a few sensible caveats when dealing with statistics, especially if there is a sensational story attached:

  • “be critical or statistics”
  • “look for a causal link or mechanism”
  • “demand scientific rigor in showing a strong statistically significant correlation”