Rolf Steyer, Michael Eid, and Peter Schwenkmezger
It is shown how to specify a structural equation model in such a way that the true intraindividual change scores between two occasions of measurement are the values of an endogenous latent variable in the model. This makes possible to explain (and/or study the correlates of) interindividual differences in intraindividual change. An empirical example with data on the mood state of well-being, a well-being trait scale, and a daily hassles and uplift scale, each assessed on four occasions of measurement, illustrates the approach.
Keywords: Intraindividual change, true scores, structural equation modeling, growth curve analysis, measurement of change