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binfang TrackerWed, 17 Jul 2024 15:55:05 GMT2024-07-17T15:55:05ZRe: Fit a Multinomial Mixed Model by Proc GLIMMIX
https://communities.sas.com/t5/Statistical-Procedures/Fit-a-Multinomial-Mixed-Model-by-Proc-GLIMMIX/m-p/491013#M25508
<P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="dimention of G matrix.png" style="width: 278px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/22863i95A2459075798AC5/image-size/large?v=v2&px=999" role="button" title="dimention of G matrix.png" alt="dimention of G matrix.png" /></span><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="covariance estimate of G matrix.png" style="width: 588px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/22864iFD955E60671AFB4F/image-size/large?v=v2&px=999" role="button" title="covariance estimate of G matrix.png" alt="covariance estimate of G matrix.png" /></span> </P><P> </P><P>Above is what the G matrix dimension and G matrix estimate is. But there is something wrong as I mentioned in the first post.</P>Wed, 29 Aug 2018 21:57:30 GMThttps://communities.sas.com/t5/Statistical-Procedures/Fit-a-Multinomial-Mixed-Model-by-Proc-GLIMMIX/m-p/491013#M25508binfang2018-08-29T21:57:30ZFit a Multinomial Mixed Model by Proc GLIMMIX
https://communities.sas.com/t5/Statistical-Procedures/Fit-a-Multinomial-Mixed-Model-by-Proc-GLIMMIX/m-p/491004#M25505
<DIV>I am trying to fit a multinomial mixed model. The outcome is a categorical variables with 4 levels and the predictors are continuous. The random intercept effect come from one variable "case" in which subjects are pairs or unmatched.</DIV><DIV> </DIV><DIV>The code, <SPAN>log, output and data set are all attached</SPAN> in this post. </DIV><DIV> </DIV><DIV><STRONG>A very serious problem in the output comes from the dimension of estimated G matrix: in the output 4 parameters are estimated in the G matrix, whereas there are supposed to be only 3.<SPAN> </SPAN></STRONG>As comparison, when a logistic mixed model is fitted, in which the outcome is 2-level categorical, only one parameter in the G matrix is estimated.</DIV><DIV> </DIV><DIV>I guess there is something wrong with the model fitting.</DIV>Wed, 29 Aug 2018 21:50:17 GMThttps://communities.sas.com/t5/Statistical-Procedures/Fit-a-Multinomial-Mixed-Model-by-Proc-GLIMMIX/m-p/491004#M25505binfang2018-08-29T21:50:17ZRe: Covariance Estimates when Fitting Generalized Linear Mixed Model
https://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/490583#M25485
<P>Hi Paige,</P><P> </P><P>The model I am trying to fit is a categorical mixed model, where the outcome is a 4-level categorical variable. <STRONG>This means there should only be 3 rows of estimate in the covariance output, but there are 4 rows instead, which is not what I expected since one level should be used as reference. </STRONG></P><P> </P><P>I have attached the modified syntax if you are interested to run. The data is attached in the next post.</P><P> </P><P>Best,</P><P> </P><P>Bin</P>Tue, 28 Aug 2018 19:07:24 GMThttps://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/490583#M25485binfang2018-08-28T19:07:24ZRe: Covariance Estimates when Fitting Generalized Linear Mixed Model
https://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/488389#M25361
<P>One estimate is 0, the other one is extremely small. And their standard error are both missing.</P>Mon, 20 Aug 2018 23:40:46 GMThttps://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/488389#M25361binfang2018-08-20T23:40:46ZCovariance Estimates when Fitting Generalized Linear Mixed Model
https://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/488318#M25358
<P><SPAN>I noticed there are something wrong with covariance estimates when fitting Generalized Linear Mixed Model, as it is shown below:</SPAN></P><P><SPAN><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="image.png" style="width: 538px;"><img src="https://communities.sas.com/t5/image/serverpage/image-id/22641i632EA0759E78960F/image-size/large?v=v2&px=999" role="button" title="image.png" alt="image.png" /></span></SPAN></P><P> </P><P><SPAN>The model is a multinomial generalized mixed model, where the outcome is a 4-level categorical variable and all the predictors are continuous.</SPAN></P><P> </P><DIV> </DIV><DIV>The SAS codes are as attached.</DIV><DIV> </DIV><DIV>Can you suggest any way to fix the problem?</DIV><DIV> </DIV><DIV>Thank you!</DIV>Mon, 20 Aug 2018 18:43:50 GMThttps://communities.sas.com/t5/Statistical-Procedures/Covariance-Estimates-when-Fitting-Generalized-Linear-Mixed-Model/m-p/488318#M25358binfang2018-08-20T18:43:50Z