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Messages - castleca

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1
Hi Dan,

When I reran the command file trying to reproduce the error, the multidimensional wle estimates now produce a mean square. No idea what the problem was, but it seems to be fixed. Thanks for your attention anyway.

Courtney

2
Hi,
I am trying to compare the person fit statistics between two models with the same data, but a different dimensional structure (a 1D model compared to a 3D model). When I ask for person fit statistics along with the WLE estimates (by specifying show cases !estimates=wle,pfit=yes), ConQuest produces what looks like a MNSQ statistic accompanying the unidimensional estimates, and a t-statistic for the multidimensional estimates. Is this correct? And if so, is there any way to get a common fit statistic, short of performing the complex calculation (Wang & Chen, 2005) myself? I have attached the WLE estimates from each model. Any help is appreciated.

Thanks,
Courtney

3
Questions and Answers / Re: JML analyses no longer working
« on: May 04, 2017, 02:30:46 PM »
Hi Alvin,

No luck - same error message after the second estimation, and no .shw file produced. Thanks for all of your help - I'll anxiously await news of the bug fix.  :)

Courtney

4
Questions and Answers / Re: JML analyses no longer working
« on: May 03, 2017, 11:46:34 AM »
Hi Alvin,

Thanks for your prompt reply. I changed the type of standard error, but the analysis still crashed. I attached a screenshot of Conquest at the time of the crash, in case it is useful. Windows throws the error - not Conquest.

Any additional help would be much appreciated.

Thank you,
Courtney


5
Questions and Answers / Re: JML analyses no longer working
« on: May 02, 2017, 04:09:37 PM »
Hello,

I am having an identical issue when I try to run JML analyses using Conquest V4. Was this problem ever resolved, and if so, how may I address it?

I have attached syntax for a minimum working example, using the dataset from Tutorial 2.

Thank you for your attention,
Courtney

6
Questions and Answers / Re: Covariance matrix is not positive definite
« on: April 07, 2017, 10:25:11 PM »
I am not sure it is possible for me to easily recreate the problem with a generic example, as I don't understand what is causing it in the first place. Could I send along my syntax and data file, to have you take a look?

Thank you for your attention,
Courtney

7
Questions and Answers / Re: Covariance matrix is not positive definite
« on: April 06, 2017, 08:27:25 PM »
Hi again - when I try to run the same dataset as a within-item model, I get the following message (at roughly the same point, 98% of the way through computing errors): Element 75 in variance/covariance matrix is negative. Check model identification: -18521.1132. The same message appears for Element 77 of the variance/covariance matrix. Could this be related to the previous issue with a between-item model? Any assistance is greatly appreciated.

Thank you,
Courtney

8
Questions and Answers / Covariance matrix is not positive definite
« on: April 06, 2017, 06:06:22 PM »
Hello,

I am trying to run a between-item multidimensional partial credit model, with 60 items, 3 dimensions, and 369 cases. The model appears to converge, and it gets 98% through computing empirical errors when it crashes and produces this error message: "Covariance matrix is not positive definite. This error is fatal." I have reexamined my command file and data files several times with no luck - I simply cannot figure out what is causing this problem. Can anyone point me in a helpful direction?

Thank you,

Courtney

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