RE: analysis of non-positive DV

From: William Bachman Date: September 21, 2011 technical Source: mail-archive.com
You can do it that way, but you are throwing away data (the baseline effect). Better to model baseline and effect. May prevent negative values as well.
Quoted reply history
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Vinogradova Svetlana Sent: Wednesday, September 21, 2011 8:26 AM To: [email protected] Subject: [NMusers] analysis of non-positive DV Dear NONMEM users, I'm analyzing a dataset of 4 patients, there are 2 types of observations for each patient - vehicle (say baseline) and dose (treatment). We want to analyze our dataset in terms of (treatment-baseline). So I've modified my dataset, and now I have only one "column" of observations for each patient: DV= (treatment-baseline). But now I have some problems because I have some negitive values in DV column. In case of some models it results in problems, for example: TEFF = TBAS + (TSLP*CP)**TALP so TSLP should be positive but it's not that right... Maybe there are some common methods to deal with this case? Thanks a lot, Svetlana
Sep 21, 2011 Vinogradova Svetlana analysis of non-positive DV
Sep 21, 2011 Sebastien Bihorel Re: analysis of non-positive DV
Sep 21, 2011 William Bachman RE: analysis of non-positive DV
Sep 21, 2011 Leonid Gibiansky Re: analysis of non-positive DV
Sep 21, 2011 Kenneth Kowalski RE: analysis of non-positive DV
Sep 21, 2011 Alan Xiao RE: analysis of non-positive DV