PROCEDURES FOR THE FACTOR ANALYTIC TREATMENT OF MEASURES OBTAINED ON DIFFERENT OCCASIONS

Five models are introduced for the factor analytic treatment of a set of measures obtained from the same sample of persons on two (and, in some cases, more) occasions. The models differ in terms of the assumptions made regarding the constancy of the factor score and factor pattern matrices on the two occasions. Least-squares procedures are developed for the estimation of the (component) scores and patterns. The application of these procedures in common-factor and image theoretical contexts is also discussed. Illustrative examples using some of the procedures are presented.