Dear mailing list: I've got a student here working with me and Jim
Hodges on degrees of freedom in hierarchical GLIM models. We were
wondering if anyone out there has an example of a hierarchical model
where WinBUGS produces a negative value of p_D using the DIC tool.
It's well known that negative p_D's can happen (strong prior/data
conflict, extreme nonlinearities in the model, massive shrinkage under
a bad parametrization, etc), but it's starting to look like this is
not as unusual a scenario as the DIC writing team originally thought
(ahem).
If you've got a little hunk of WinBUGS code that delivers a negative
p_D, would you be willing to email it to me at [log in to unmask]
Naturally we will reference you in anything we eventually write up
(assuming we can get anything beautiful to come out!).
Thanks and Cheers -- Brad Carlin
-------------------------------------------------------------------
This list is for discussion of modelling issues and the BUGS software.
For help with crashes and error messages, first mail [log in to unmask]
To mail the BUGS list, mail to [log in to unmask]
Before mailing, please check the archive at www.jiscmail.ac.uk/lists/bugs.html
Please do not mail attachments to the list.
To leave the BUGS list, send LEAVE BUGS to [log in to unmask]
If this fails, mail [log in to unmask], NOT the whole list
|