NONMEM Users Network Archive

Hosted by Cognigen

Re: [NMusers] In covariate analysis, should we use p-value or OFV to decide which model is better when comparing?

From: Jakob Ribbing <jakob.ribbing_at_pharmetheus.com>
Date: Sun, 24 Feb 2019 09:18:35 +0100

Dear Sumeet,

I assume Pirana is merely running PsN, and you can find good =
documentation for each PsN program, in the PsN documentation:
https://uupharmacometrics.github.io/PsN/ =
<https://uupharmacometrics.github.io/PsN/>

For this specific question, you should probably not use the gof option =
and instead specify p-values for forward and backward selection.
The gof option is only used in special cases, where one does not want to =
assume that delta-OFV follows a chi-square distribution (or if one wants =
to use p-values lower than 0.00000001).

Best regards

Jakob




Jakob Ribbing, Ph.D.

Senior Consultant, Pharmetheus AB



Cell/Mobile: +46 (0)70 514 33 77

Jakob.Ribbing_at_Pharmetheus.com

www.pharmetheus.com <http://www.pharmetheus.com/>

Phone, Office: +46 (0)18 513 328

Uppsala Science Park, Dag Hammarskjölds väg 52B

SE-752 37 Uppsala, Sweden



This communication is confidential and is only intended for the use of =
the individual or entity to which it is directed. It may contain =
information that is privileged and exempt from disclosure under =
applicable law. If you are not the intended recipient please notify us =
immediately. Please do not copy it or disclose its contents to any other =
person.





> On 23 Feb 2019, at 21:28, Singla, Sumeet K <sumeet-singla_at_uiowa.edu> =
wrote:
>
> Dear all,
>
> In step-wise covariate analysis (scm) option in Pirana, there is an =
-gof option in configuration file to let software know whether we should =
use OFV or p-value. My question is, which one we should use while =
comparing the models in scm analysis? P-value or OFV?
>
> Regards,
> Sumeet Singla
> Graduate Student
> Dpt. of Pharmaceutics & Translational Therapeutics
> College of Pharmacy- University of Iowa



Received on Sun Feb 24 2019 - 03:18:35 EST

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to: nmusers-request@iconplc.com. Once subscribed, you may contribute to the discussion by emailing: nmusers@globomaxnm.com.