poisson回归结果异常

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请问SAS中使用多因素Poisson回归运行结果出现很大的β和RR（如β=21.07，RR=1423148556.64）这种情况有没有办法可以调整的？(下面是程序，x1 x2 x3 x4 x6是分类变量，x5、x7是定量变量）
data poisson;   /*hiv发病poisson回归分析*/
set a;
run;
ods html;
proc genmod;
class x1 x2 x3 x4 x6;
model person/year= x1 x2 x3 x4 x5 x6 x7/link=log dist=poi LRCI OBSTATS RESIDUALS alpha=0.05 type1 type3 scale=deviance;
ODS OUTPUT ParameterEstimates=AA Obstats=CC;
run;
DATA BB(DROP=StdErr ChisqProbChisq LowerLRCL UpperLRCL);
set AA ;
RR=EXP(Estimate);
LCI=EXP(LowerLRCL);
UCI=EXP(UpperLRCL);
PROC PRINT;
RUN;
ods html close;

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关键词：Poisson回归 poisson 回归结果 Iss son 回归分析 person

The direct problem is, for some reference cell, the rate is too low and probably too close to 0 and thus overflate other categories's estimates. I bet, in your dataset, you have many such records, like: person =0, year =..., etc.
It is not normal for a model setting like that, i.e., events/trails, in count log-linear model, which implies # of events occuring on the number of bernulli trials (binomial). More commonly seen is to use offset variable.

jingju

Yeah, your assumption is right, the rate is really low. I have tried to use offset in the model, but it is not helpful. What should I do to make it better?

推广的Poisson分布—Stuttering Poisson分布https://bbs.pinggu.org/thread-1523734-1-1.html

try using negtive binary distrbution,many times,nb distribution is better than poisson