```Date: Fri, 9 Oct 1998 15:26:28 +0200 Reply-To: Paul Dickman Sender: "SAS(r) Discussion" From: Paul Dickman Subject: Re: user-defined deviance in GENMOD Comments: cc: Hans-Peter Piepho In-Reply-To: <199810091218.OAA23377@e45.it.ki.se> Content-Type: text/plain; charset="iso-8859-1" Hi Hans-Peter, The outcome is the number of successes, not the proportion. If you define mu=_MEAN_ then you'll need to use v=mu*(1-mu/n). Alternatively, define mu=_MEAN_/n and use v=n*mu*(1-mu). If we call O the observed number of successes and E the expected (fitted) number of successes out of N trials, then the deviance increment is given by d=2[O ln (O/E) + (N-O) ln{(N-O)/(N-E)}] I would suggest the following code: v=_MEAN_*(1-_MEAN_/n); d=2*(_y*log(_y/_MEAN_) + (N-_y)*log((N-_y)/(N-_MEAN_))); I haven't tested this and would be interested to hear if it works. Cheers Paul ----- Paul Dickman (paul.dickman@onkpat.ki.se) Cancer Epidemiology Unit, Radiumhemmet, Karolinska Hospital, 171 76 Stockholm, Sweden Ph: +46 8 5177 5375 Fax: +46 8 326 113 -----Original Message----- From: SAS(r) Discussion [mailto:SAS-L@AKH-WIEN.AC.AT]On Behalf Of Hans-Peter Piepho Sent: Friday, 9 October 1998 12:52 To: SAS-L@AKH-WIEN.AC.AT Subject: user-defined deviance in GENMOD Hi all, I have tried to use the GENMOD options for userdefined deviances and variance functions. When specifying the binomial deviance and variance function, I get strange results, which do not coincide with those obtained for the "dist=bin link=logit" call. Does someone known whether this is a bug? proc genmod; class t b; mu=_MEAN_; _y=_RESP_; d=-2*( _y*log(mu/(1-mu)) + log(1-mu) ); v=mu*(1-mu); deviance dev=d; variance var=v; model m/n=b t t*b/link=logit type1; run; proc genmod; class t b; model m/n=b t b*t/dist=bin link=logit type1; run; Hans-Peter _______________________________________________________________________ Hans-Peter Piepho Institut f. Nutzpflanzenkunde WWW: http://www.wiz.uni-kassel.de/fts/ Universitaet Kassel Mail: piepho@wiz.uni-kassel.de Steinstrasse 19 Fax: +49 5542 98 1230 37213 Witzenhausen, Germany Phone: +49 5542 98 1248 ```

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