RE: time-to-event simulation based diagnostic
Dear Francois,
Unless you create a new data set where events are allowed to occur at any
possible time (usually a dense time grid), then the result that you have got
is rather the expected (i.e. too good to be true).
Best regards,
Mats
Mats Karlsson, PhD
Professor of Pharmacometrics
Dept of Pharmaceutical Biosciences
Faculty of Pharmacy
Uppsala University
Box 591
75124 Uppsala
Phone: +46 18 4714105
Fax + 46 18 4714003
Quoted reply history
From: [email protected] [mailto:[email protected]] On
Behalf Of Francois Gaudreault
Sent: 19 September 2012 22:49
To: [email protected]
Subject: [NMusers] time-to-event simulation based diagnostic
Dear NONMEM users
I am currently performing a time-to-event analysis on binary data using a
weibull distribution (time-varying hazard function).
Using simulation based diagnositcs, I compared `simulated kaplan-Meier` to
`observed kaplan-Meier`. However, fit looks to good to be true and I was
actually suspecting a mispecification during the simulation process with PsN
Here is the code used for vpc:
vpc run2.mod -tte=RTTE -flip_comments -samples=100
I used (ICALL.EQ.4) and the flip-comment option in the model file. However,
I am not sure if I have to generate a new simulation data set (each
individual having a row for each possible observation time) or use the
original one ?
Any advises or comments are welcome
Regards,
--
François Gaudreault, Ph.D. Candidate
Pharmacométrie / Pharmacometrics
Chargé de cours / Lecturer
Faculté de pharmacie / Faculty of Pharmacy
Université de Montréal