ERIC Number: ED044424
Record Type: RIE
Publication Date: 1970-Mar
Reference Count: 0
Suppressor Variables, Prediction, and the Interpretation of Psychological Relationships.
Conger, Anthony J.; Jackson, Douglas N.
The suppressor variable, a variable wholly uncorrelated with a criterion, but which nevertheless improves prediction because of its relationship with a predictor, is critically examined. For a suppressor so defined, formal identities are shown with part, partial, and multiple correlational procedures. It is demonstrated that if maximum prediction is the primary goal, the use of the suppressor approach is appropriate if, and only if, the suppressor-criterion correlation is zero. Otherwise multiple correlation will always yield a higher validity. Mathematical constraints are shown to be operating on suppressors with a resultant effect of producing minimal incremental validity for suppressors within the range of typical validity coefficients. It is also demonstrated that additional predictors will yield a greater increment in prediction in comparison with suppressors. On the other hand, because of its conceptual advantages, the formally equivalent part correlation is recommended over the multiple correlation approach for suppressor variables which enter into theoretical relationships and for the measurement of latent constructs. (Author/DG)
Publication Type: N/A
Education Level: N/A
Authoring Institution: University of Western Ontario, London.