Fwd: RE: VPC for non-uniform sampling

Dear Ayappa, "Standardized Visual Predictive Check" are in fact prediction discrepancies which were developed by Mentré et al., with a decorrelated version called normalised prediction distribution errors (npde) in Brendel et al. npde are available in Nonmem or Monolix. There is also a library in R to help compute both pd and npde (the library is called npde). Here are a few links to the original publications. Prediction discrepancies and their evaluation: Prediction discrepancies for the evaluation of nonlinear mixed-effects models. Mentré F, Escolano S. J Pharmacokinet Pharmacodyn. 2006 Jun;33(3):345-67. Epub 2005 Nov 13. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1989778/ The development of npde: Metrics for external model evaluation with an application to the population pharmacokinetics of gliclazide. Brendel K, Comets E, Laffont C, Laveille C, Mentré F. Pharm Res. 2006 Sep;23(9):2036-49. Epub 2006 Aug 12. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2124466/ An evaluation of the npde: J Pharmacokinet Pharmacodyn. 2010 Feb;37(1):49-65. Epub 2009 Dec 23. Evaluation of different tests based on observations for external model evaluation of population analyses. Brendel K, Comets E, Laffont C, Mentré F. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874574/ The npde library for R: Computing normalised prediction distribution errors to evaluate nonlinear mixed-effect models: the npde add-on package for R. Comets E, Brendel K, Mentré F. Comput Methods Programs Biomed. 2008 May;90(2):154-66. Epub 2008 Jan 22. http://www.hal.inserm.fr/inserm-00274332/en/ And I leave you with a very fitting question in the light of Jean's response :-) Why Should Prediction Discrepancies Be Renamed Standardized Visual Predictive Check? Comets E, Brendel K, Mentré F. J Clin Pharmacol. 2011 Sep 10. [Epub ahead of print] http://www.hal.inserm.fr/inserm-00627625/fr/ All the best, Emmanuelle -------- Message original -------- Sujet: [NMusers] RE: VPC for non-uniform sampling Date : Tue, 10 Jan 2012 22:30:59 +0000 De : Lavigne, Jean <[email protected]> Pour : Ayyappa Chaturvedula <[email protected]>, "[email protected]" <[email protected]> Dear Ayyappa, You may consider using "Standardized Visual Predictive Check" published in the following links: http://jcp.sagepub.com/content/52/1/39 http://www.page-meeting.org/pdf_assets/4050-Standardized%20Visual%20Predictive%20Check%20in%20Model%20Evaluation%20-%20PAGE2009%20submit.pdf Best regards, Jean *From:*[email protected] [mailto:[email protected]] *On Behalf Of *Ayyappa Chaturvedula *Sent:* Tuesday, January 10, 2012 5:11 PM *To:* [email protected] *Subject:* [NMusers] VPC for non-uniform sampling Dear expert users, I am working on a dataset where subjects were sampled at different visits at random. I have developed a model for the data but not sure how to do a VPC as they do not have the same sampling scheme. I appreciate some guidance in this. Regards, Ayyappa This electronic transmission may contain confidential and/or proprietary information and is intended to be for the use of the individual or entity named above. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this electronic transmission is prohibited. If you have received this electronic transmission in error, please destroy it and immediately notify us of the error. Thank you.