glm error message when using family Gamma(link="inverse")
On Tue, 9 Dec 2008, John Sorkin wrote:
R 2.5
Please 1) do as the posting guide asks, and quote version numbers accurately. 2) do as the posting guide asks, and update *before* posting. That's too old a version to support here.
windows XP I am getting an error from glm() that I don't understand. Any help or suggestions would be appreciated. N.B. 1<=AAMTCAREJ<=327900
summary(data$AAMTCAREJ)
Min. 1st Qu. Median Mean 3rd Qu. Max.
1.0 404.3 1430.0 6567.0 5457.0 327900.0
fitglm<-glm(AAMTCAREJ~sexcat+H_AGE+SmokeCat+InsuranceCat+MedicadeCat+
+ incomegrp+racecat+MARSTATJS+EdCat+bmiNewjohn,data=data,family=Gamma(link = "inverse")) Error: no valid set of coefficients has been found: please supply starting values In addition: Warning message: NaNs produced in: log(x)
That model is not necessarily valid: the linear predictor has to be strictly positive. If you really know why it is applicable you will be able to give starting values (e.g. maybe all the columns of the design matrix are positive, in which case you will be able to find suitable positive initial coefficients).
Thanks
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
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