[R-sig-ME] logLik (old-fashion way) for mixed-effects models

Christian Salas christian.salas at yale.edu
Thu Apr 16 11:03:48 CEST 2009

If i already fit a lm() model, i can obtain the log-likelihood [i do not
  want to use AIC()] using the residuals from the model, and using the
  RMSE of the model as sigma for my normal pdf. This would be in R like

 > sum(dnorm(-resi,mean=0,sd=sigma,log=T))  [1]

  if i fit a gls model i can do the same

  for a lme() model, i know that we cannot just use the same loglik model
  [1], because they are different. I wonder if somedody already have 
some syntax in R similar to [1] but for  mixed-effects models, i mean 
something that compute the log-likelihood but without using lme() 
directly as summary(lme.obj)$AIC

  thanks in advance!

Christian Salas                     E-mail:christian.salas at yale.edu
PhD candidate                       http://environment.yale.edu/salas
School of Forestry and Environmental Studies
Yale University                     Tel: +1-(203)-432 5126
360 Prospect St                     Fax:+1-(203)-432 3809
New Haven, CT 06511-2189            Office: Room 35, Marsh Hall

Yale Biometrics Lab                  http://environment.yale.edu/biometrics

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