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ERIC Number: ED426102
Record Type: Non-Journal
Publication Date: 1999-Jan
Pages: 24
Abstractor: N/A
Reference Count: N/A
Illustrations of the Basic Concepts Involved in Testing for Moderator/Mediator Variable Effects.
Chevalier, Shirley A.
An important but too infrequently considered methodology that can be used in research, especially research focusing on Pearson's "r" (B. Walsh, 1996) or the multiple "R" (see B. Thompson, 1992) involves testing for moderator or mediator variable effects. As explained by M. Gall, W. Borg, and J. Gall (1996), moderator analysis "involves identifying a subgroup for whom the correlation between a criterion and a predictor variable is significantly greater than the correlation for the total sample from which the group was formed" (p. 425). A study by M. Zeidner (1987) provides a concrete example of this methodology. Zeidner studied the relationship between aptitude test performance and grade point average. However, he believed that this relationship would be moderated by age (be different across age groups). Therefore, he computed "r" across four different age groups, and found that values differed considerably across age, as expected. Techniques for evaluating these effects are explained and illustrated. In a sense, these dynamics can be related to the "restriction of range" effect (an influence on "r" caused by the variance in the sample; correlation will increase or decrease depending on the range of subjects studied) so widely misunderstood within the social sciences. (Contains 2 figures and 17 references.) (Author/SLD)
Publication Type: Reports - Descriptive; Speeches/Meeting Papers
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A