Not too long ago, I received a call from a distressed client. Let’s call her Nancy.
Nancy had asked for advice about how to run a repeated measures analysis. The advisor told Nancy that actually, a repeated measures analysis was inappropriate for her data.
Nancy was sure repeated measures was appropriate and the response led her to fear that she had grossly misunderstood a very basic tenet in her statistical training.
Nancy had measured a response variable at two time points for two groups: an intervention group, who received a treatment, and a control group, who did not.
Both groups were measured before and after the intervention.
Nancy was sure that this was a classic repeated measures experiment with [Read more…] about Analyzing Pre-Post Data with Repeated Measures or ANCOVA