Regression to the Mean

Surface

Regression to the mean describes how unusual results tend to move closer to average on later measurements. If your first observation is extremely high or extremely low, randomness and noise are usually part of the story. In the next round, the luck component has less room to repeat in the same way, so the number drifts back toward typical values.

Middle

This is why we fall for “patterns” in streaks. We notice the dramatic points and forget the invisible baseline, the variability that was always there. The brain wants narrative continuity, so it interprets fluctuation as destiny. But statistics says the more surprising the first measurement, the more likely it is to be less extreme next time, even when nothing meaningful changed.

Deep

Regression to the mean is a quiet lesson in humility. It does not mean outcomes are meaningless. It means your interpretation might be. When you measure, you should ask what would be expected if randomness were doing most of the work. Then you can tell the difference between a real effect and a mirage created by a single moment in the data.