# Repeated measures ANOVA within and between factors

I have conducted repeated measures ANOVA, with 2 factors: One within factor (time, pre-post intervention) and one between factor (treatment, two groups). I have measured different dependent variables. I find in all the cases an effect of the within factor, an effect of the between factor, and only in some cases an interaction between both. I want to know how to interpret these results.

• What does the interaction mean?
• Is the significance of the factor treatment (between) sufficient to be able to say that one group is superior to other one, that one treatment is better?

EDIT: The measures I took in three moments are: time spent using technologies, frecuency of use, abuse.. The significant interaction is for within factor (moment) X between factor (group), but it's only significant for the time spent using technologies. What means the sugnificance of between factor? Why it's important the intetaction? Thanks

The measures I took in three moments are: time spent using technologies, frecuency of use, abuse.. The significant interaction is for within factor (moment) X between factor (group), but it's only significant for the time spent using technologies. What means the sugnificance of between factor? Why it's important the intetaction? Thanks

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I think you need to be more specific about the problem. What is the model? What factors were significant and which ones weren't? –  Michael Chernick Aug 31 '12 at 20:06
If you have both pre vs. post & treatment1 vs. treatment2, & they were significant but the interaction wasn't, then you may have had a failure of randomization. You want your pre-treatment observations to be equivalent & only your post-treatment observations to differ. Ie, you want your interaction to be significant, but your main effects not to be. Also, if you have >1 DV, you should probably be doing MANOVA. –  gung Aug 31 '12 at 22:46
Then, the most important result is the interaction? The allocation to the different conditions was random. Thanks –  Clara Sep 1 '12 at 9:29
This is a program of prevention of technological addictions. One of the conditions or groups is the traditional program and the other contains additional control techniques. The total sample comprised 1160 students. I have three measures: pre, post and follow-up. –  Clara Sep 1 '12 at 9:41
The dependent variables are several: the frequency of use, time of use, the degree of dependence ... There are no differences between the previous groups, homogeneous groups. I've done ANOVA and MANOVA. For example, I find an effect of between and within factor when I take pre-post dates. And only appears a significant interaction (time X group) for the time of use. My doubt is what means each one of the effects. I don't know if I can say that by having a significant factor between, there is a treatment that produces a superior improvement. I don't understand the meaning of the interaction –  Clara Sep 1 '12 at 9:42