Posted by
Swank, Paul R on
Nov 28, 2006; 2:35pm
URL: http://spssx-discussion.165.s1.nabble.com/More-on-Repeated-Measures-tp1072284p1072288.html
Ahhhh.
With this model, you get multivariate tests for the multiple DVs and
multivariate tets for the repeated measures factors. This is known as a
doubly multivariate analysis. You may either interpret the two
mulitvariate tests, or the multivariate tests for the DVs and the
univariate tests for the repeated measures portion of the design. The
latter is sometimes called a multivariate mixed model because it
combines both multivariate and univariate tests. The decsion to make is
whether the repeated measures portions meets the sphericity assumptions.
If not, the the doubly multivariate design may be better but is assumes
multivariate normality across both sets of variates.
Paul R. Swank, Ph.D.
Professor, Developmental Pediatrics
Director of Research,
University of Texas Health Science Center at Houston
-----Original Message-----
From: S Elgie [mailto:
[hidden email]]
Sent: Wednesday, November 22, 2006 8:02 PM
To: Swank, Paul R;
[hidden email]
Subject: Re: More on Repeated Measures
Hi Paul,
The design I am testing has eight measures at three time periods, and I
am conducting a multivariate repeated meassures analysis. The design is
completely repeated with no between-subjects factor(s). I do get
univariate results, but what is puzzling me is the two tables containing
multivariate tests (Pillais and so on), one labelled 'Multivariate
Tests'
and the other 'Tests of Within-Subjects Effects.'
Thanks!
Susan
>From: "Swank, Paul R" <
[hidden email]>
>Reply-To: "Swank, Paul R" <
[hidden email]>
>To:
[hidden email]
>Subject: Re: More on Repeated Measures
>Date: Wed, 22 Nov 2006 16:00:56 -0600
>
>The multivariate tests assume multiariate normality and homegenous
>variance covariance matrices across groups, the univariate repeated
>measures assumes homegeneity of variance covariance matrices,
>sphericity of the variance covariance matrix and normality of the
>residuals. The univariate repeated measures is typically mor sensisitve
>since the violation of sphericity tends to result in more significant
>results. The tests are different and do have different degress of
freedom.
>
>
>Paul R. Swank, Ph.D.
>Professor, Developmental Pediatrics
>Director of Research,
>
>
>University of Texas Health Science Center at Houston
>
>-----Original Message-----
>From: SPSSX(r) Discussion [mailto:
[hidden email]] On Behalf
>Of S Elgie
>Sent: Wednesday, November 22, 2006 2:39 PM
>To:
[hidden email]
>Subject: More on Repeated Measures
>
>Thanks so much for all help received on repeated measures. I am
>emboldened to ask a further question. When one does a multivariate
>repeated measures analysis, there are two tables of multivariate
>results. The first is labelled 'Multivariate Tests' and contains tests
>of the intercept and within subject factor. (For now let's assume just
>one repeated factor). The second table is labelled 'Tests of
>Within-Subjects Effects' and contains just the tests of the repeated
>factor. I have not ever had the problem of these two tables giving
>substantially different answers, such as one significant and the other
>not. But the numbers and degrees of freedom etc.
>are different and I have never been sure why and particularly not sure
>which one should be reported.
>
>Thanks again,
>
>Susan
>
>QQ Consulting
>Toronto Canada
>
[hidden email]