Paunonen and Jackson (1988) demonstrated
that stepwise moderated regression provides a test
of interaction effects that protects the nominal
Type I error rate. However, the stepwise procedure
has also been characterized as failing to detect
interaction effects in empirical studies. This issue
has led to questions regarding the method’s
statistical power (Bobko, 1986; Zedeck, 1971) in
applied research. It is demonstrated that, because
of a research strategy frequently used in empirical
investigations, the probability of Type II error in
detecting a true interaction effect is unknown.
Specifically, the number of scale steps used in
measuring the dependent variable is shown to
result in a form of systematic error that can
spuriously increase or decrease the expected effect
size of the interaction. The problem is also discussed
in the context of testing more complex models.
Recommendations for eliminating this problem in
future research designs are provided. Index terms:
information loss, interaction effects, Likert scales,
moderated regression, response transformation.
Russell, Craig J, Pinto, Jeffrey K & Bobko, Philip. (1991). Appropriate moderated regression and inappropriate research strategy: A demonstration of information loss due to scale coarseness. Applied Psychological Measurement, 15, 257-266. doi:10.1177/014662169101500305
Russell, Craig J.; Pinto, Jeffrey K.; Bobko, Philip.
Appropriate moderated regression and inappropriate research strategy: A demonstration of information loss due to scale coarseness.
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