lavaan and indicators without error

28 views
Skip to first unread message

scorla

unread,
Jul 12, 2020, 6:45:21 PM7/12/20
to lavaan
Hello guys!

I'm trying to do a CFA for simulated data. This data has two latent variables with three indicators each, whereas each indicator has a factor loading of 1.

My model looks like this:
"f1 =~ v1 + v2 + v3
f2 =~ v4 + v5 + v6
f2 ~ f1"

In certain cases, all indicators for f1 and/or f2 are generated without error. Unfortunately, lavaan gives the following error when trying to run a CFA:

sample covariance matrix is not positive-definite

When I fix the residual variance of all indicators of f1 and/or f2, I get another error message:
initial model-implied matrix (Sigma) is not positive definite;
check your model and/or starting parameters.

Is lavaan simply not able to deal with data that comes without measurement error?

Yves Rosseel

unread,
Jul 16, 2020, 2:02:10 PM7/16/20
to lav...@googlegroups.com
On 7/13/20 12:45 AM, scorla wrote:
> sample covariance matrix is not positive-definite

Note that you created the sample covariance matrix (in the simulation).

You should check this (eg by checking that all eigenvalues are positive)
before you call lavaan.

Yves.
Reply all
Reply to author
Forward
0 new messages