New Contributor
Posts: 3

# Corr matrix not positive definite

Hey!

I want to do a path analysis with proc CALIS but I keep getting an error that my correlation matrix is not positive definite.

Is there a way to make the matrix positive definite? Its a 43 x 43 lower diagonal matrix I generated from Excel. I don't want to go about removing the variables one by one because there are many of them, and that will take much time too.

Thanks!

Super User
Posts: 23,683

## Re: Corr matrix not positive definite

How did you calculate the correlation matrix? I would recommend doing it in SAS so your full process is reproducible.
New Contributor
Posts: 3

## Re: Corr matrix not positive definite

Thanks. I'll get the Corr matrix with SAS for a start.

Posts: 2,989

## Re: Corr matrix not positive definite

A correlation matrix can fail "positive definite" if it has some variables (or linear combinations of variables) with a perfect +1 or -1 correlation with another variable (or another linear combination of variables).

In that case, you would want to identify these perfect correlations and remove at least one variable from the analysis, as it is not needed.

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Paige Miller
New Contributor
Posts: 3

## Re: Corr matrix not positive definite

Thanks. I'll check the matrix for such variables.

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SAS Super FREQ
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