ABSTRACT
This chapter introduces the analysis of repeated-measures data, in which multiple measurements are made on the same subject (unit of analysis) under different conditions or across time. Repeated-measures data sets can be considered to be a type of two-level data, in which Level 2 represents the subjects and Level 1 represents the repeated measurements made on each subject. Covariates measured at Level 2 of the data (the subject level) describe between-subject variation and Level 1 covariates describe within-subject variation. The data that we analyze are from an experimental study of rats in which the dependent variable was measured in three brain regions for two levels of a drug treatment. Brain region and treatment are crossed within-subject factors; measurements were made for the same brain regions and the same treatments within each rat. Between-subject factors (e.g., sex or genotype) are not considered in this example.
