In a two-group study, in which participants are matched on a measure that has much random measurement error (had poor reliability), which of the following would be the most serious threat to the study's validity?
A) history
B) regression
C) testing
D) instrumentation

Question

Quizplus · Accepted Answer

Regression to the mean is a threat when participants are matched on a measure with poor reliability, as extreme scores tend to move closer to the average upon retesting, potentially confounding the results.

In a Two-Group Study, in Which Participants Are Matched on a Measure