Fact or artefact: an item response theory analysis of median split based repressor classification
Many studies have investigated the phenomenon of repression. Repressors are defined as individuals who deny or avoid the experience of negative affect. A common method for the identification of repressors is a median split approach using questionnaires that measure anxiety and social desirability. The present study aimed to evaluate this most frequently used procedure using a psychometric model.
We applied item response theory using model assumptions comparable with those of the median split approach to detect repressors and examine the appropriateness of the median split procedure.
A mixed sample of 655 students and members of the general public completed the two scales usually used to identify repressors, namely the Taylor Manifest Anxiety Scale and the Marlowe-Crowne Social Desirability Scale.
Employing item response theory mixture-model analyses, we were unable to replicate the median split solution on a latent level.
Our results did not support the identification of repressors via dichotomization of the two scales. The median split approach does not appear to detect repressors satisfactorily. The implications of the results for the conceptualization and assessment of repressors are discussed.
Statement of contribution
What is already known on this subject? Repression is a construct describing the suppression, denial or failure to exhibit negative emotions, and has been associated with many health outcomes. In much of the literature, two self-report scales are used to identify repressors, one measuring manifest anxiety and the other measuring social desirability. Median splits on these scales identify people low in manifest anxiety and high in self-reported social desirability as repressors.
What does this study add? Using item-response theory we examined whether median splits are an appropriate method to identify repressors. We found that the latent classes did not show the characteristic pattern suggested by the median split approach and concluded that the psychometric model did not support the classification of individuals via median splits. Our findings have implications for future work using the repression construct and median splits to identify repressors.