Which ANOVA?



Hi there,

For some work I'm doing, I have a set of data looking at treatments. There are 3 independent groups (control, CBT, CBT+antidepressants). Each individual has 2 pieces of data- before and after treatment.

My question is, which ANOVA would be most suitable if I want to find out whether CBT is an effective treatment? And secondly, does combing CBT with anti-depressant treatment increase the overall effectiveness?

Any help would be greatly appreciated! Thank you :)


I think that a three-way ANOVA is the most appropriate in this instance. To determine if CBT with anti-depressant treatment increases the overall effectiveness, you will need to look at the coefficient just before the CBT variable. In context, assume that the coefficient is 12.45, then we would assume that CBT increases effectiveness by 12.45%. That is, a unit increase in CBT will generate a 12.45% in the overall effectiveness.