Error with median c-hat

questions concerning analysis/theory using program MARK

Error with median c-hat

Postby caspar » Thu Jun 05, 2008 12:12 pm

Hi all,
Has anyone ever encountered the error: "Invalid Link Function specified for true model." when trying to run a median c-hat GOF test on a multistrata model? Or perhaps anyone knows where this error stems from?
It might be worth adding that I use different link functions for S and p (sin) than for Psi (logit).

Thanks in advance

Caspar
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Postby gwhite » Thu Jun 05, 2008 1:37 pm

Caspar:
The invalid link function is associated with the true model parameters. When you do simulations, you should use the identity link and an identity design matrix for the parameters of the true model, and then specify the real parameter values.
I suspect you have used MLogit links in your model, since the sin and logit link functions are supported. The median c-hat simulator does not know about the MLogit link for generating data. So, you need to re-run the model with other standard link functions. Unfortunately, using other link functions may cause convergence problem with the estimation model. So, at the moment, I don't have a perfect solution for you.

Gary
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Postby caspar » Fri Jun 06, 2008 5:24 am

Hi Gary,
Thanks for your reply! I did suspect the Mlogit issue, but using a model without Mlogits (thus logits) for the Psi parameters leads to the same error.

The issue might arise I suspect because I have used the sin link for the S and p parameters, and logit for Psi, based on what has been said earlier http://www.phidot.org/forum/viewtopic.p ... highlight= on such design matrices.
Does this maybe explain the error?

Thanks,

Caspar
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Posts: 14
Joined: Sun Jul 22, 2007 7:33 am


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