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: [email protected] > To: [email protected]; [email protected] > 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 > > > > 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 > >
