[程式] SAS proc genmod的警告

看板Statistics作者 (工口工口)時間11年前 (2014/10/04 18:48), 11年前編輯推噓0(0推 0噓 9→)
留言9則, 1人參與, 最新討論串1/1
[軟體程式類別]: SAS [程式問題]: 由於為sparse data 產生以下警告訊息 WARNING: The generalized Hessian matrix is not positive definite. Iteration will be terminated [軟體熟悉度]: 高(1年以上) [問題敘述]: 再跑GEE模型分析的時候，由於資料在某個時間為sparse data SAS無法估計，有試過加改maxiter修改收斂次數，可是依然出現警告訊息 想請問是否有其他的option可以調整，以解決此問題 [程式範例]: PROC GENMOD data=patient2 DESCEND ; CLASS group (ref="2") sex SN PreVac40_B(ref="0"); MODEL SR_all= Age Kt_V group PreVac40_B BUN Ferritin time /Dist=bin link=logit maxiter=100000 ; REPEATED SUBJECT=SN/type=exch; run; -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 140.116.52.59 ※ 文章網址: http://www.ptt.cc/bbs/Statistics/M.1412419735.A.5EA.html
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10/04 20:30, , 1F
outcomes in some subgroups are all zero or one.
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or the subgoups defined by a covariate are subsets of
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those defined by another covariate. You might want to
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pay special attention to PreVac40_B (I suppose this
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indicates that a subject's baseline antibody titer is
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10/04 20:38, , 6F
>=1:40), and other covariates that may affect antibody
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level, including gender and age.
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感謝您的回覆,您提的這兩個問題我們都有想過, 現階段想嘗試解決第一個可能的問題-sparse data 不過查過許多SAS mannual和其他人的code都找不到解決方案... ※ 編輯: tokyo291 (140.116.52.59), 10/05/2014 19:55:01
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10/05 22:42, , 8F
如果大部份的observation都是0,為什麼硬是要fit這個model
10/05 22:42, 8F
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10/05 22:43, , 9F
Consider reduce the number of covariates.
10/05 22:43, 9F
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