Re: 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, 赵赵 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. Ｉfind 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
>