What is Regression Toward the Mean?
Regression toward the mean is a statistical phenomenon where extreme measurements tend to be followed by more moderate ones. This concept, first observed by Sir Francis Galton in the 19th century, has significant implications in various fields, including psychology, sports, and economics.
Key aspects of regression toward the mean include:
Natural variation: Extreme scores often result from a combination of true ability and luck (good or bad)
Subsequent measurements: These are likely to be closer to the average due to the reduced influence of chance factors
Misinterpretation: Often mistaken for real change or the effect of interventions
Importance in research: Researchers must account for this phenomenon to avoid drawing false conclusions
Examples of regression toward the mean include:
A star athlete’s performance fluctuating over a season
Test scores varying between attempts
Stock market returns evening out over time
Understanding this concept is crucial for accurately interpreting data and making informed decisions in various fields.