Dear Maurice,
Negative shrinkage means that your SD is bigger than your estimated
omega. And your negative shrinkage is near 0 (<-1%). Therefore, I would
take it for a null shrinkage.
Best Regards,
David
Chenguang Wang a écrit :
Dear all,
I have found a negtive ETA shrinkage result in my model output. I did a
simple simulation with 1-compartement model via iv bolus administration,
and then refitted the simulated data with the same model and initial
values. In the NONMEM output (of NONMEM 7), I got ETAshrink(%):
-2.0123E-01 -2.3271E-01. From the definition of ETA shrinkage:
1-SD(eta*)/omega, eta* is the EBE estimated eta, there is no constraint
preventing ETA shrinkage going below zero. Could somebody give me an
interpretation of negtive ETA shrinkage?
Thanks in advance!
Maurice
