Posted by
Mike on
Jun 17, 2011; 1:37pm
URL: http://spssx-discussion.165.s1.nabble.com/Comparing-Correlation-Matrices-tp4498609p4498794.html
Hi,
First, I would suggest that you test the equality of covariance matrices
instead of correlation matrices.
Second, Box's M test is test of equality of covariance matrices and is
a available in SPSS in MANOVA and DISCRIMINANT (if that procedure
is still available). Karl Wuensch briefly covers this on his statistics website
where he reproduces responses by David Nichols and Joop Hox on this
question back in 1994 and 1997; see:
http://core.ecu.edu/psyc/wuenschk/StatHelp/ComparingCorrelationMatrices.htmDave notes that if you convert the variables into z-score form, then Box's
M test become a test of equality of correlation matrices. As Joop points out,
SEM/Covariance Structure Analysis (CSA) is more robust.
Third, Barbara Byrne who appears to be in the business of teaching people
of how to use the various SEM program to perform different types of SEM
analyses, has an article on how to do testing of equality of covariance in the
journal Structural Equation Modeling. Here is a link to the abstract of the
article:
http://www.informaworld.com/smpp/content~db=all~content=a785833114The article was published in 2004 and might have to be modified to take
into account recent developments in SEM.
Fourth, one example of a study that uses equality of covariance structures
to test whether groups receiving different modes of administration of a
scale is this one published in the journal Clinical Trials:
James W Varni, Christine A Limbers, and Daniel A Newman
Using factor analysis to confirm the validity of children's self-reported
health-related quality of life across different modes of administration
Clin Trials April 2009 6: 185-195, doi:10.1177/1740774509102309
The authors work through several different types of analyses to examine
the nature of the underlying relationships.
Others, I'm sure, can provide additional advice.
-Mike Palij
New York University
[hidden email]
----- Original Message -----
From: "Salbod, Mr. Stephen" <
[hidden email]>
To: <
[hidden email]>
Sent: Friday, June 17, 2011 8:36 AM
Subject: Comparing Correlation Matrices
> Good Morning SPSSers,
>
> I want to determine whether the relations among six subscales for the students and parents differ. A colleague administered a 73 item parenting scale, consisting of six subscales (e.g., subscales A thru F), to 95 8th graders and their parents (just one parent). The school requested that neither students' responses nor their parents' responses be identifiable; that is, the scales were administered without any identification codes. Therefore, the problem is how do I compare two independent matrices?
>
> Green (1992) suggests a SEM solution. He provides a LISREL VI program. I'm not sure how to use convert into AMOS code to solve my particular problem.
> I would appreciate if someone can point me in the right direction: reference or example.
>
> TIA
>
> Stephen Salbod, Pace University, NYC
>
> Green, J. A. (1992). Testing whether correlation matrices are different from each other. Developmental Psychology, 28(2), 215-224.
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