danger of summary metrics.pdf

Danger of

Summary Metrics

It can be misleading to only look at the summary metrics of data sets.

To demonstrate the effect, statistician Francis Anscombe put together four example data sets in the 1970s. Known as Anscombe’s Quartet, each data set has the same mean, variance and correlation. However, when graphed, it’s clear that each of the data sets are totally different. The point that Anscombe wanted to make is that the shape of the data is as important as the summary metrics and cannot be ignored in analysis.