There is a longstanding debate on whether the analysis of covariance (ANCOVA) or the change score approach is more appropriate when analyzing non-experimental longitudinal data. In this article, we use a structural modeling perspective to clarify that the ANCOVA approach is based on the assumption that all relevant covariates are measured (i.e.,…

Educational large-scale assessment (LSA) studies like the program for international student assessment (PISA) provide important information about trends in the performance of educational indicators in cognitive domains. The change in the country means in a cognitive domain like reading between two successive assessments is an example of a trend…