What is Noise? - KDnuggets

If two felons receive sentences of three years and seven years when they should both be sentenced to five, the difference is due to noise. The average of three and seven is indeed five, but justice has quite obviously not been served! It reminds me of the joke about the three statisticians on a hunt: the first one overshoots by a foot, the second one undershoots by a foot, and the third one says, "Got him!" In practice, errors of this sort don't cancel out but add up, with regrettable repercussions. A defendant's sentence should not depend on which judge the case happens to be assigned to, and yet it does.