RE: [NMusers] Coding for simulation

2014-03-26 Thread Åstrand , Magnus
Dear All Another solution would be to first generate (or add) the WT, GENDER and Genotype and put these in the indata set, with R most of what you are doing in NONMEM would be just 2-3 lines of code. I you want to peruse this I could guide you on how to. Also, a comment on the NONMEM code below,

[NMusers] SV: Standard errors of estimates for strictly positive parameters

2015-02-12 Thread Åstrand , Magnus
Dear all, an alternative which I try to use on strictly positive parameters is to estimate on log-scale. Then I think often the assymptitic approximation is more true and the resulting measures of parameter uncertainty are more reliable. BW Magnus Från:

[NMusers] RE: Using MCP-MOD in dose finding for Phase 3

2015-03-20 Thread Åstrand , Magnus
Dear Nele, here are some thoughts: The idea with the MCPmod is twofold, a) provide a procedure for testing for a treatment effect and in that test incorporate all doses studies and still maintain control of type I error. b) If significance in a) continue with framework for estimating the dose

SV: [NMusers] Ambiguous independence of independent variable.

2015-09-30 Thread Åstrand , Magnus
Hi Matts, I agree on your conclusions and think the issue of missing data is a very similar problem. There the missing completely at random and missing at random would match your examples a and b. For missing data there exists litterature and also perhaps a better understanding among

RE: [NMusers] $PRIOR with normal for OMEGA?

2016-11-11 Thread Åstrand , Magnus
Hi To add on Martin’s suggestion, one item to think of when using theta for estimating the variances of eta is to use log scaled STD as your model parameter, so instead of THETA*ETA (with OMEGA fixed) use exp(THETA)*ETA. This way you would assume a log-normal prior for the standard deviation of

[NMusers] RE: question about random seed for simulation

2017-03-09 Thread Åstrand , Magnus
Hi Penny, I suspect you are right in your conclusion that number of records for each id matters in this case. My solution to your problem would be to add columns for IIV to your dataset outside of NONMEM. Quite easily done in R. Use the rmvnorm R function to simulate your etas, 600 rows times