I have conducted a clinical trial using two groups with two different treatment modalities. I have measured different physical and biochemical parameters (e.g pulse, systolic blood pressure, serum sodium level etc.) in each group at different time intervals (say pre-intervention, after 1 month and after two months). Now I want to measure the effect of each treatment modality on these parameters over time and at the same time look for any significant difference existing between the two groups. Is this study design suitable for repeated measures ANOVA? How to do it then in SPSS 19? Is there any other way to do the analysis?

  • $\begingroup$ I've added the tag sequential-analysis as it sounds like you want to do sort of interim analysis. I may well be wrong, so feel free to revert to RM ANOVA if that applies. $\endgroup$ – chl Aug 17 '12 at 21:23

You could do a repeated measures ANOVA (over time, e.g. pre/1 mo/2 mo) for each of your DVs separately. I don't have a copy of SPSS at the present time, but this primer looks about right.

If your dependent measures are moderately correlated (rs = .4 to .7), you may want to consider looking into a MANOVA or creating some composite measures. Unfortunately, I do not know much about how to conduct a MANOVA inside SPSS. So, I leave that to better minds.


If I am understanding you correctly, RPT ANOVA is often used for this type of analysis.

measures/parameters: physical, biochemical

factors: treatment, group, time

treatment x time = RPT measures ANOVA

what specific group differences do you want to test for? in measures? over time or on average?

you may find this very helpful http://www.ucdenver.edu/academics/colleges/nursing/Documents/PDF/RepeatedMeasuresANOVA.pdf


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