LISREL set covariance to 0

[Maria Wynne]

In LISREL, how can I set the covariance between two factors to zero?

Thanks,

Maria

[statisticsdoc]

Maria,

You want to constrain the relevant elements of the phi matrix to zero
(assuming that your factors are exogenous variables, or that you are simply
fitting a measurement model).

If you are using syntax, you can set the covariance between factors 1 and 2
to zero by:

FI PH(1,2) .

or

FI PH 1 2  .

This assumes that the other factors have by default been allowed to covary.
The command will set the parameter to zero.

BTW, if you want to fix the covariance to some value other than zero, you
will also need the VA command.

VA 0.2 PH(1,2)

or

VA 0.2 PH 1 2.

in combination with the FI command will set the covariance to 0.2

HTH,

Stephen Brand



P.S. You asked about LISREL - you can also accomplish this task with
SIMPLIS.





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design, visit
www.statisticsdoc.com


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]]On Behalf Of
Maria Wynne
Sent: Thursday, February 15, 2007 12:55 PM
To: [hidden email]
Subject: LISREL set covariance to 0


In LISREL, how can I set the covariance between two factors to zero?

Thanks,

Maria