A Legitimate Case of Component Analysis of Ipsative Measures, and Partialling the Mean as an Alternative to Ipsatization

Abstract

Ipsatizing variable prior to component analysis, by subtracting the man score of each individual from all scores of that individual, has met with serious criticisms, both strategic and technical. On the other hand, the procedure is still popular in the study of personality, as a means of removing acquiescence variance. An attempt is made at reconciling these facts. Technical objections to component analysis of ipsatized variables, recently restated by Dunlap and Cornwall, are shown to be based on erroneous premises. A strategic objection leveled by Clemans does apply in a majority of cases, but has no bearing on the specific case of ipsatizing responses to personality questionnaires made up of opposite item pears. As an alternative to ipsatizing by subtraction of the mean, partialling the mean component is suggested as a more elegant procedure, allowing a breakdown of explained variance into variance due to the mean and to subequent components uncorrelated with the mean.