In this lesson, we will be discussing the basics of cross-over repeated measure designs. A cross-over design is a repeated measures design in which each experimental unit is given each of the different treatment levels over the course of the experiment. This means that over time each experimental unit is assigned to a specific ordered sequence of different treatment levels. This is in contrast to a repeated measures design in time, discussed in the previous lesson, where multiple measurements from the same experimental unit assigned to a specific treatment level are taken through time.