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Thread: evaluation of treatment efficacy in a cohort of people considering a single variable

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    evaluation of treatment efficacy in a cohort of people considering a single variable




    Hello, I have to evaluate the treatment efficacy in a cohort of people over a year (so I have 4 groups of data, one for each 3 months) considering a single variable. This variable is ordinal (goes from 0 to 9) and of course the 4 groups of data are referred to the same persons. Which statistic test shall I use? I thought about t-test (but which one?) but maybe theres something more appropriate.
    I use SPSS.
    thank you very much

    example

    followup t0 t1 t2 t3
    .
    person1: 2 4 4 5
    person2: 1 3 2 5
    person3: 0 0 1 1
    ....

    p.s. I could also perform this statistic using a three year database, so the groups of data will be much more

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    no one can help me?

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    hi,
    what is exactly the question you need to answer with the test?
    regards
    rogojel

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    I can compare the cohort of person undergoing the threatment with another cohort undergoing a different one. basically the dataset is huge and some of them chose a treatment, some another, the rest went for placebo. For all of them the initial conditions were the same and there was a three months follow-up.
    I need a test that makes me answer the question: which treatment is the best?
    thank you so much

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    Could you describe your dependent variable in more detail? Maybe it could
    be treated as an interval scaled measure.

    How large are your 3 samples? And is it correct to assume that no randomization
    was used to allocate subjects to groups?

    With kind regards

    K.
    Last edited by Karabiner; 09-18-2013 at 03:14 AM. Reason: typo corrected

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    the samples contain more than 300 records each
    the dependent variable is a score that is related to an effect. it goes from 0 to 9
    yes, unfortunately no randomization has been done

    thank you so much

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    the dependent variable is a score that is related to an effect. it goes from 0 to 9
    I am afraid that this is not very informative. Is it a rating scale? A physical measurement?
    Was it already used and validated in other studies? How was it treated there, always as
    ordinal scaled?
    unfortunately no randomization has been done
    A repeated measures (mixed) ANOVA would be straightforward,
    with time of measurement as within-subjects factor and group
    as between subjects factor. But this assumes an interval scaled
    dependent variable.

    With kind regards

    K.

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari

    your assumption was right about the variable. So the anova fits this dataset better? and what type of?

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    Re: evaluation of treatment efficacy in a cohort of people considering a single vari


    It was described in my last post.

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