RE: Question: FO VS. FOCE VS. FOCE-INTER in POSTHOC 2014-1-3
Dear Dr Leonid
Thanks so much! Your answer gave me a very clear direction of what to do next. Still, I just wonder the reason,the principle behind it. Would you please give me a further explanation?
Thanks in advance
Regards,Zhao
> Date: Sun, 5 Jan 2014 10:56:17 -0500
> From: lgibiansky
> To: zhaochenyanvictory ail.com; nmusers
> Subject: Re: [NMusers] Question: FO VS. FOCE VS. FOCE-INTER in POSTHOC 2014-1-3
>
> Zhao,
>
> For MAXEVAL=0, FOCE and FO should provide identical results (POSTHOC is
> needed for FO; for FOCE it is not necessary but you can use it as well).
> Concerning INTER, it should be used in all cases except when the error
> is purely additive (and you can use it even for additive error, this
> should not affect your solution). So if you need POSTHOC run, the
> recommendation is to use
>
> $ESTIMATION MAXEVAL=0 METHOD=1 INTER NOABORT POSTHOC
>
> in all cases. For external validation, VPC-style diagnostics (as well as
> regular model diagnostic plots) would be preferable to the overall
> measures like MPE or RMSE that are more or less useless in identifying
> the direction of the bias (if you have any differences with the
> literature models).
>
> Leonid
>
>
> --------------------------------------
> Leonid Gibiansky, Ph.D.
> President, QuantPharm LLC
> web: www.quantpharm.com
> e-mail: LGibiansky at quantpharm.com
> tel: (301) 767 5566
>
>
>
Quoted reply history
> On 1/4/2014 9:31 PM, wrote:
> > Dear all,
> >
> > First of all, I wanna say HAPPY NEW YEAR to you guys. Best Wishes in
> > this very beginning day of the "Horse Year"(Chinese calendar lol )
> >
> > Well,as titled, here is the question:
> >
> > I'm now doing external validation of the PPK models pubished before by
> > other groups with my own data. find extreme differences in MPE(mean
> > prediction error), RMSE(root of mean squared prediction error) and so on
> > while using different estimation methods like FO, FOCE, or FOCE-INTER,
> > especially the one with interaction from the former 2.
> >
> > I do understand the diversity in these 3 methods. But how much is the
> > influence as to POSTHOC in external validation. For example:
> >
> > $ESTIMATION MAXEVAL=0 METHOD=1 NOABORT POSTHOC
> >
> > Could anybody explain to me and clarify the problem?
> >
> > Great thanks!
> >
> > Yours
> >
> > Zhao Chenyan
> >
> > Department of Clinical Pharmacy, Huashan Hospital, Fudan University,
> > Shanghai, P.R.China
> >