AMOS error: moment matrix is not positive definite

[Nabaneeta Saha]

Hello,

I am trying to run a path analysis with AMOS but I am getting the error
message:

Minimization unsuccessful.

The sample moment matrix is not positive definite. It could fail to be
positive definite for any of the following reasons:
1. The sample covariance matrix or correlation matrix contains a data
entry error
2. The observed variables are linearly dependent
3. The sample covariance matrix was computed from incomplete data using
the method pairwise deletion
4. The sample correlation matrix contains correlation coefficients
other than product moment correlations.

The message tells me to allow non-positive values for the matrix, I did so,
but still I am getting the error message

Could anyone please let me know where am I going wrong. It would really be
of great help.

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[Rich Ulrich]

Well, the fundamental thing that you are doing wrong is what the
message tells you -- You are trying to do an analysis without a
real covariance matrix (that is, one generated from a large
enough N to make make it positive definite).

I don't know what sort of errors it would be, that Amos might
be able to work around.  But apparently your problem is worse.

a) What are you using for covariance/correlation?  Describe,
or maybe show it, too.
b) Fix it.

 --
Rich Ulrich

> Date: Mon, 27 Feb 2012 23:22:28 -0500

> From: [hidden email]
> Subject: AMOS error: moment matrix is not positive definite
> To: [hidden email]
>
> Hello,
>
> I am trying to run a path analysis with AMOS but I am getting the error
> message:
>
> Minimization unsuccessful.
>
> The sample moment matrix is not positive definite. It could fail to be
> positive definite for any of the following reasons:
> 1. The sample covariance matrix or correlation matrix contains a data
> entry error
> 2. The observed variables are linearly dependent
> 3. The sample covariance matrix was computed from incomplete data using
> the method pairwise deletion
> 4. The sample correlation matrix contains correlation coefficients
> other than product moment correlations.
>
> The message tells me to allow non-positive values for the matrix, I did so,
> but still I am getting the error message
>
> Could anyone please let me know where am I going wrong. It would really be
> of great help.
> ...

[David Marso]

One or more of the stated reasons is probably correct!
How many cases?  How many variables?  Have you googled Non-Positive Definite Matrix to learn what such a situation implies and what possible remedies may be applied.  Perhaps consider attaching your moment matrix file to your next message and perhaps someone will take the time to look at it.

------

Nabaneeta Saha wrote

Hello,

I am trying to run a path analysis with AMOS but I am getting the error
message:

Minimization unsuccessful.

The sample moment matrix is not positive definite. It could fail to be
positive definite for any of the following reasons:
1. The sample covariance matrix or correlation matrix contains a data
entry error
2. The observed variables are linearly dependent
3. The sample covariance matrix was computed from incomplete data using
the method pairwise deletion
4. The sample correlation matrix contains correlation coefficients
other than product moment correlations.

The message tells me to allow non-positive values for the matrix, I did so,
but still I am getting the error message

Could anyone please let me know where am I going wrong. It would really be
of great help.

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD

[Frans Marcelissen-3]

An illegal cov matrix can also be the result of pairwise deletion of missing values, especially
when the number of missings is high. I have the impression that this is the most frequent occurring reason.
Frans
 

> Date: Mon, 27 Feb 2012 20:45:55 -0800

> From: [hidden email]
> Subject: Re: AMOS error: moment matrix is not positive definite
> To: [hidden email]
>
> One or more of the stated reasons is probably correct!
> How many cases? How many variables? Have you googled Non-Positive Definite
> Matrix to learn what such a situation implies and what possible remedies may
> be applied. Perhaps consider attaching your moment matrix file to your next
> message and perhaps someone will take the time to look at it.
>
> ------
>
> Nabaneeta Saha wrote
> >
> > Hello,
> >
> > I am trying to run a path analysis with AMOS but I am getting the error
> > message:
> >
> > Minimization unsuccessful.
> >
> > The sample moment matrix is not positive definite. It could fail to be
> > positive definite for any of the following reasons:
> > 1. The sample covariance matrix or correlation matrix contains a data
> > entry error
> > 2. The observed variables are linearly dependent
> > 3. The sample covariance matrix was computed from incomplete data using
> > the method pairwise deletion
> > 4. The sample correlation matrix contains correlation coefficients
> > other than product moment correlations.
> >
> > The message tells me to allow non-positive values for the matrix, I did
> > so,
> > but still I am getting the error message
> >
> > Could anyone please let me know where am I going wrong. It would really be
> > of great help.
> >
> > =====================
> > To manage your subscription to SPSSX-L, send a message to
> > LISTSERV@.UGA (not to SPSSX-L), with no body text except the
> > command. To leave the list, send the command
> > SIGNOFF SPSSX-L
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> > INFO REFCARD
> >
>
>
> --
> View this message in context: http://spssx-discussion.1045642.n5.nabble.com/AMOS-error-moment-matrix-is-not-positive-definite-tp5520824p5520840.html
> Sent from the SPSSX Discussion mailing list archive at Nabble.com.
>
> =====================
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> [hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
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> INFO REFCARD

[Nabaneeta Saha]

My sample number was not sufficient and I also missed the covariance in the model.

Thanks to list for their suggestions.

On Tue, Feb 28, 2012 at 9:52 AM, Nsaha6 <[hidden email]> wrote:

Hello,

I am trying to run a path analysis with AMOS but I am getting the error
message:

Minimization unsuccessful.

The sample moment matrix is not positive definite. It could fail to be
positive definite for any of the following reasons:
1. The sample covariance matrix or correlation matrix contains a data
entry error
2. The observed variables are linearly dependent
3. The sample covariance matrix was computed from incomplete data using
the method pairwise deletion
4. The sample correlation matrix contains correlation coefficients
other than product moment correlations.

The message tells me to allow non-positive values for the matrix, I did so,
but still I am getting the error message

Could anyone please let me know where am I going wrong. It would really be
of great help.