WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed.

RubenPnx — Fri, 07 Nov 2014 15:12:16 GMT

Hi all,

I am trying to get the seasonal estimates of the breeding population (% of the breeding population in a concrete period) from diverse Species in the different seasons of the year. To note that I have obtained this data from diferent longitudinal studies, having unbalanced data. So I am using:

Population to control the pseudoreplication

ID_study to control the different samplings,

Species (Genus*Family) to take into account the taxonomy

However, I would like to take into account the density using it as offset. The problem is that when I include this term in orocethe SAS code I get the following answer: "WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed".

proc glimmix data=breeding method=laplace plots=(ResidualPanel(conditional marginal));

class Season Species Genus Family Population ID_study Month ;

model Breed_population = Season Month (Season)

/dist=beta offset=Density

ddfm=none covb s;

random intercept / subject = Population (ID_study);

random intercept / subject= Species (Genus*Family);

nloptions maxiter=150;

lsmeans Season/cl diff PLOT=diff (NOabs center) adjust=tukey;

lsmeans Season/cl ilink;

run;

Anyone know how I can overcome this problem?

Thanks,

Rubén

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed.

RubenPnx — Mon, 10 Nov 2014 12:38:38 GMT

The warning was due to the amount of decimals of the offset. When I reduce it to 2-3 decimals I could to carry out the model.

I hope it may help someone

Sorry for the inconvences!!!

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WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed.

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed.