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Thread: How to analyze change in performance

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    How to analyze change in performance




    Greetings,

    I have a task that two groups of participants completed at Time 1 and Time 2. I was planning to conduct a repeated measures ANOVA, but also want to explore the change in performance (diff between Time 1 and Time 2) between the groups. I could conduct a t-test on this separate question, but wondering if there is another option. Any thoughts much appreciated.

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    Re: How to analyze change in performance

    Why would a repeated measure ANOVA not explore the difference between time one and two? That is what repeated measure ANOVA's are used for.
    "Very few theories have been abandoned because they were found to be invalid on the basis of empirical evidence...." Spanos, 1995

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    Re: How to analyze change in performance


    When people pose this question, I always ask if group assignment was randomized or not. If not, you could have different initial values for y between groups, in which differences may mask these differences. Thus you may need to control for baseline value in your model. In addition, even if baseline values seem comparable in a non-randomized design, you could still have an omitted variable (confounder) that biases your results if not controlled for via modeling or sensitivity analysis.
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