This tutorial[1] is an optional supplement to the courseware of the Centre for Social Sciences - Psychology at Athabasca University. It is used as an enhancement to Athabasca University's Psychology 304 (Research Methods in Psychology). It was authored by Dr. David Polson, Adjunct Assistant Professor at the University of Victoria. Dr. Cheuk Ng and Lorna Brown of Athabasca University provided various content-related, technical and instructional-design assistance.


Part 1 of this tutorial contains an overview of factorial designs along with an illustrative example. Rudimentary data analysis associated with the design is also discussed. Finally, where applicable, special considerations and pitfalls of the design are highlighted.

In Part 2, you are asked to identify whether or not each of the 13 experiments is an example of factorial designs. Many questions contain a second part that require you to determine whether or not data from that experiment suggest a treatment effect.


Following many of the vignettes in Part 2 of this tutorial, a reference is made to a Related Source. This reference is included for students interested in pursuing the subject matter of the vignette. Sometimes the details of the experiment outlined in the vignette are very similar to the Related Source, but in other cases they are quite different. Thus, the experiment as presented is not to be regarded as an accurate description of the Related Source - the commonality between the two may simply be similar independent and dependent variables.

1 This tutorial was adapted from a tutorial "Experimental Designs: Factorial, Interrupted Time Series, and Regression Discontinuity" originally developed by Dr. David Polson for PSYC 404 (Experimental Psychology), which was closed in 2005. Very minor changes were made by Dr. Cheuk Ng in January of 2007.