In Chapter 2, simple methods to analyse longitudinal data are introduced. First, methods for analysing the change over time for longitudinal studies with two repeated measurements. Second, methods for analysing the change over time for longitudinal studies with more than two repeated measurements. And finally, methods for analysing the difference in the change over time between groups for longitudinal studies with both two and more than two repeated measurements. Although both the parametric and non-parametric versions of these methods are discussed, a very detailed explanation of GLM for repeated measures is provided. All methods are accompanied by extensive real-life data examples.