I have a response variable measured at three time points per individual (week 0, 18, and 36). I am interested in differences in the change of the response over the 36 weeks within some categorical variable X.
I see two ways of modeling this.
One way ANOVA with response =
week_36_score - week_0_score(this seems like the simplest option)
Repeated Measures ANCOVA with response =
week_36_score. Covariate =
- Which would you prefer (if any, maybe there is a better choice)?
I know there has been a lot of articles on this and they seem to say each has its own strengths and weaknesses. I believe the second model would have more power. I am not worried about a ceiling effect here.