What Is Regression to the Mean? How Does It Threaten

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Examlex · Accepted Answer

The Answer is Regression to the mean is a statistical phenomenon where extreme or unusual data points are likely to be followed by more typical or average data points. In other words, if a variable is measured at an extreme value, it is likely to move closer to the average on subsequent measurements.

This phenomenon threatens internal validity in research studies because it can lead to the misinterpretation of results. For example, if a study measures the effects of a new intervention on a group of individuals who are selected because they have extreme scores on a certain outcome variable, regression to the mean can make it appear as though the intervention had a positive effect when in reality, the change is simply due to the natural tendency for extreme scores to move closer to the average over time.

To address this threat to internal validity, researchers can use control groups, random assignment, and pre-post measurements to ensure that any observed changes are truly due to the intervention and not just the result of regression to the mean. Additionally, using multiple measurements over time can help to identify and account for the effects of regression to the mean in the data analysis process.

What Is Regression to the Mean? How Does It Threaten

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