[R-sig-ME] [Fwd: testing quasi-likelihood in glmer with simulations]

Ben Bolker bolker at zoology.ufl.edu
Mon Sep 29 21:01:20 CEST 2008



  I spent a bit of time this weekend running simulations
of quasi-likelihood estimation in glmer. The results
are posted at

http://www.zoo.ufl.edu/bolker/glmm/quasitest.pdf
http://www.zoo.ufl.edu/bolker/glmm/quasitest.Rnw

  I confirmed my suspicion that glmer is scaling the
random-effects variance-covariance matrix by the
scale parameter when it shouldn't; I also discovered
that the quasi-likelihood fit to lognormal-Poisson-distributed
data is alarmingly (?) biased, although a lognormal-Poisson
fit with individual-level random effects works nicely.

  Any comments are welcome.

  cheers
   Ben Bolker




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