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ERIC Number: EJ823368
Record Type: Journal
Publication Date: 2003-Dec
Pages: 12
Abstractor: As Provided
Reference Count: 0
ISSN: ISSN-1092-4388
Explaining and Controlling Regression to the Mean in Longitudinal Research Designs
Zhang, Xuyang; Tomblin, J. Bruce
Journal of Speech, Language, and Hearing Research, v46 n6 p1340-1351 Dec 2003
This tutorial is concerned with examining how regression to the mean influences research findings in longitudinal studies of clinical populations. In such studies participants are often obtained because of performance that deviates systematically from the population mean and are then subsequently studied with respect to change in the trait used for this selection. It is shown that in such research there is a potential for the estimates of change to be erroneous due to the effect of regression to the mean. The source of the regression effect is shown to arise from measurement error and a sampling bias of this measurement error in the process of selecting on extreme scores. It is also shown that regression effects are greater with measures that are less reliable and with samples that are selected with more extreme scores. Furthermore, it is shown that regression effects are particularly prominent when measures of change are based on changes in dichotomous states formed from quantitative, normally distributed traits. In addition to a formal analysis of the regression to the mean, the features of regression to the mean are demonstrated via a simulation.
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A