Split-Plot Factorial Design

It is often inconvenient, costly, or even impossible to perform a factorial design in a completely randomized fashion. An alternative to a completely randomized design is a split-plot design. The use of split-plot designs started in agricultural experimentation, where experiments were carried out on different plots of land. Classical agricultural split-plot experimental designs were full factorial designs but run in a specific format. The key feature of split-plot designs is that levels of one or more factors are assigned to entire plots of land referred to as whole plots or main plots, whereas levels of other factors are assigned to parts of these whole or main plots. These parts are called subplots or split-plots. Split-plot designs thus have two types of experimental units, whole plots ...