In an attempt to correct our analyses for regression dilution bias (27), we calculated
regression toward the mean based on these data and found larger effects sizes than for uncorrected estimates.
Elmer, "Estimating the effect of
regression toward the mean under stochastic censoring," The American Journal of Epidemiology, vol.
We also compared both solutions with an untreated control group, a comparison that is rarely performed but which is necessary to control for
regression toward the mean. Finally, we measured symptoms after stopping sinus irrigation, to gain new information about the rate of relapse of symptoms.
Mlodinow provides lessons on what he calls "a field of subtlety," from the basic laws of probability, to
regression toward the mean and availability bias.
During expansion in the 1990s, a large percentage of risk contract enrollees tended to be recent joiners, who may be healthier than long-term enrollees because of
regression toward the mean (Welch, 1985; Riley, Rabey, and Kasper, 1989).
Any factor that reduces the correlation between two sets of scores contributes to
regression toward the mean. We discuss five: errors of measurement, conditional errors of measurement, differential growth, changes in the content of the developmental scale, and changes in the norming sample.