The shrinking of the big data promise

Markets do not have much patience for a commitment to techniques that don’t deliver. Unfortunately, spy agencies aren’t subject to this discipline “Regression to the mean” is one of the subtlest concepts in statistical literacy – and yet it’s terribly simple. In plain English, “regression to the mean” is the idea that normally, things are pretty normal. That is, if you observe something abnormal – a high fever, a high share price, a long, unseasonable stretch of sunny or rainy