Re: Question regarding Calculation Process in $DES BLOCK

On 5/26/2011 1:52 AM, Li Li wrote: > When I output DDT1, the table will be: > Subject Time (hr) DDT1 > 1 0 4??? [...] > 2 0 5??? [...] > Why the DDT1 for subject 1 at first time point is 4 and subject 2 at > first time point is 5? Why it holds the last time point value of each > subject? In the output, nonmem tells you that this is going to happen: " (WARNING 48) DES-DEFINED ITEMS ARE COMPUTED ONLY WHEN EVENT TIME INCREASES. E.G., DISPLAYED VALUES ASSOCIATED WITH THE FIRST EVENT RECORD OF AN INDIVIDUAL RECORD ARE COMPUTED WITH (THE LAST ADVANCE TO) AN EVENT TIME OF THE PRIOR INDIVIDUAL RECORD. " A related caveat is that during integration between two time points, the value of data items (in the $DES block) are set to the values defined at the end time, not the start time. I'm afraid that I can't give you a good explanation for this design decision. Kind regards, -- Paul Matthias Diderichsen, PhD Quantitative Solutions B.V. +31 624 330 706