Regression to the Mean

When an extreme event occurs in an sample, subsequent samples are likely to return to the mean value1. This is important when considering extreme events and then reacting to them. A return to the mean or a return to normal does not mean that reaction had any impact to cause the return.


References

1.
Tetlock, P. E. & Gardner, D. Superforecasting: The Art and Science of Prediction. (Crown, New York, 2015).