Dear Indrajeet, The objective function value reported is the -2 times Log likelihood and this is minimized to get the estimates for your model parameters. So when the log-likelihood is greater than 1, -2* log-likelihood gives a negative value. Therefore, running in to negative objection value does not affect the precision of the parameter estimated.
Thanks Mathangi Mathangi Gopalakrishnan Center for Translational Medicine School of Pharmacy University of Maryland, Baltimore From: [email protected] [mailto:[email protected]] On Behalf Of indrajeet singh Sent: Sunday, May 13, 2012 9:30 PM To: [email protected] Subject: [NMusers] Negative Obj Function What does negative objective function really mean other than the fact that mathematically speaking likelyhood is greater than 1? Does this affect the reliability of estimate of parameters? I am running into negative Obj Func but parameter estimates seems to be ok. Any comments ? Best Jeet -- Indrajeet Singh,PhD Sr. Clinical Pharmacokineticist Abbott Labs, North Chicago, IL
