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Picture of user. suzannejak Joined: 01/06/2010

Chi-Square Confidence Interval

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Fit Functions
Dear all,

I used the following line to obtain a confidence interval around the chi-square, but I received an error that this key is not found in the mxOptions.

model1a = mxOption(model1,"Chi-Square Confidence Intervals", "Yes")

Indeed, when I ask for "getOption('mxOptions')" the option does not seem to exist. Is this true? Or am I doing something wrong?

Thanks in advance!
Suzanne

Posted on
Picture of user. t0mpr1c3 Joined: 12/14/2009

individual likelihood statistics (classic Mx MX%P)

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Fit Functions
Is there some way to export the likelihood function for a vector of observations equivalent to the 1st column of the classic Mx MX%P= command?
Posted on
No user picture. jenslane Joined: 03/05/2010

gxe in the presence of rge unrestricted baseline model

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Fit Functions
Hello -
I'm using a gxe in the presence of rge model and was wondering if I need to first run an unretricted baseline model to determine the minimized value of -2lnL of the data. If so, does anyone have a script for this?

Posted on
No user picture. rlucas Joined: 11/17/2009

SRMR with missing data

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Fit Functions
I'm trying to create a function to calculate SRMR, but I'm not sure how to do this when there are missing data. Does anyone have suggestions about what observed covariance matrix to use when there are missing data (or does anyone know what mplus or amos use to get SRMR with missing data)?

Also (and I'm sure this is much easier), how can I get the predicted covariance matrix among observed variables in OpenMx? I'm sure this is obvious, but I couldn't figure out how to pull this out of the output.

Thanks!

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Picture of user. Ryne Joined: 07/31/2009

Comparing -2LL for ML and FIML models

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Fit Functions
A few months back, I spent a few days banging my head against a wall trying to figure out how to relate the -2LL from a covariance model to that of a FIML model so we could make FIML models with no missing data and no definition variables go much faster. The two -2LLs differed by almost exactly 2*pi*n*nvar (the likelihood of the data, as we termed it), but not exactly, and I could never make the right correction.
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Picture of user. carey Joined: 10/19/2009

potential optimization problem

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Fit Functions
There MAY be a problem with the optimization using some likelihood functions in OpenMx. Specifically, the gradient and the standard errors from the output slots in an MxModel are congruent with minimizing -log(L). The calculatedHessian, however, is congruent with minimizing -2log(L). The attached R code provides an illustration.

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Picture of user. 0avasns Joined: 12/09/2010

A function to return fit indices

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Fit Functions
This is something that would be really useful if someone who is actually competent in the area would fix it. I did make a start, and I know that some of this is wrong; some is probably not sufficiently general; and some does indeed match the sem output exactly. So it is a start. Someone, please fix it and include with OpenMx, this would be very useful for a whole bunch of ignoramuses like me who occasionally need to run an SEM or path analysis and aren't covered by the sem package (e.g., need multi-group models).

# starter R code to compute the usual assortment of fit indices
#

Posted on
No user picture. ferrito Joined: 06/03/2010

Proportion of variance

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Fit Functions
Hi,
I have performed a modification sreach and did all I could do however the fit statistics are really bad -

I have a proportion of variance of 92% strangely enough. What does this mean?

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