search for: glimmix

Hi, I am trying to fit a model with lmer in R and proc glimmix in SAS. I have simplified my code but I am surprised to see I get different results from the two softwares. My R code is : lmer(y~age_cat + (1|cat),data=fic,family=binomial(link = "logit"), NaGQ=1) My SAS code is : ods output Glimmix.Glimmix.ParameterEstimates=t_estimates; proc gli...

Hello. Some months age an e-mail was posted in which a comparison between Glimmix and glm was discussed. I have not been able to find that e-mail on the R archive. Does anyone recall the date of the above e-mail? Thank you very much. ******************************************* Antonio Paredes USDA- Center for Veterinary Biologics Biometrics Unit 510 South 17th Street, Suite...

I'm fitting generalized linear mixed models to using several fixed effects (main effects and a couple of interactions) and a grouping factor (site) to explain the variation in a dichotomous response variable (family=binomial). I wanted to compare the output I obtained using PROC GLIMMIX in SAS with that obtained using lmer in R (version 2.6.1 in Windows). When using lmer I'm specifying method="PQL" so as to make the estimation method comparable between lmer and GLIMMIX. It is difficult to compare the outputs for the interaction terms because SAS gives the estimates a...

Dear R users, I've been trying to find an R package which does the PL estimation of spatial GLMMs especially with the negative binomial model. so it would be something similar to the "proc GLIMMIX" with the PL method in SAS. I've looked up some possible packages related to GLMMs, but it doesn't seem to be anyone using the PL estimation. Thanks for your help! Fei He UCR Statistics -- View this message in context: http://r.789695.n4.nabble.com/Pseudolikelihood-Estimation-of-s...

...ject. Most of the subjects have two responses and in almost all cases the responses are identical although the explantory factor values are not always identical for each subject. If I use geeglm from geepack, I get reasonable estimates close to the naive model results. I also tried using the SAS glimmix macro to fit a generalized mixed model and the routine does not converge. Why does geeglm appear to work but not lmer and glmmPQL? Is this likely to be due to my particular data set? Rick B.

Dear R Users, May be this message should be directy send to Douglas Bates ... I just want to know if I can use the AIC value given in the output of an lmer model to classify my logistic models. I heard that the AIC value given in GLIMMIX output (SAS) is false because it come from a calculation based on pseudo-likelyhood. Is it the same for lmer ??? thanks, Arnaud Arnaud MOSNIER Biologiste Ph.D. Département de Biologie Université du Québec à Rimouski 300 Allée des Ursulines Rimouski, Québec, G5L 3A1 Tél. : 723-1986 poste 1653...

...mixed model. I used SAS but I want to redo the same analysis in R. Here the SAS code and what I wrote in R. It seems to work but the results are not the same. I don't know how to specify the class variable in R or specify the variance matrix. Can you please help me? Thanks Jurgen ## SAS: proc glimmix data=trend method=RSPL; class pid; model mdrfinal (event = '1') = time therapy comment / dist=binary link=logit solution cl; random intercept / subject=pid type=un; run; ## R: model_GLMM<- glmmPQL(mdrfinal ~ time + therapy + comment, data = data, family = binomial, random = ~1|...

...uper_numeric.c, line 613 Moreover, if I test yet another continuous variable "vitality", to my surprise R just crashes completely. This is a mystery to me, especially because the variables totmas or vitality don't give any problem when I build the exact same models in SAS with proc glimmix... Does someone have experience with this type of problem? Thank you in advance, Martijn. -- Martijn Vandegehuchte Ghent University Department Biology Terrestrial Ecology Unit K.L.Ledeganckstraat 35 B-9000 Ghent telephone: +32 (0)9/264 50 84 e-mail: martijn.vandegehuchte@ugent.be we...

...me a p< 2.2e-16 ***, concluding that "spikes" has a highly significant effect on "aphids". However, when I look at the summary of model1: summary(model1) I find a t-value for "spikes" of -0.1166 which is really insignificant... When I try model1 in SAS with proc glimmix, corrected for overdispersion with "random _residual_", it also gives a p-value for "spikes" of 0,985. So if "spikes" is not having a significant effect on "aphids", then why the above mentionned p-value generated by anova in R? Can anyone explain this? Pl...

...a covariate. Additionally, the residual variance in the data is a negative function of the covariate, which I would like to model as well. Working in SAS, I was able to do this on transformed data in PROC MIXED, but ran into trouble trying to run it as a logistic regression in the original scale in GLIMMIX. Can glmer in lme4 do this? It seems that "weights" in lme4 refers to weighting of observations rather than modeling the variance-covariate, as it does in nlme. I tried running nlme, but I'm stuck on syntax, particularly with regards to how the fixed and random statements should...

Hello, Might anyone know how to conduct Wald-type F-tests of the fixed effects estimated by glmmPQL? I see this implemented in SAS (GLIMMIX), and have seen it recommended in user group discussions, but haven't come across any code to accomplish it. I understand the anova function treats a glmmPQL fit as an lme fit, with the test assumptions based on maximum likelihood, which is inappropriate for PQL. I'm using S-Plus 7. I also...

...as sampled from three different level, district,school,individual, so this was regarded as a multilevel dataset. I hope to fit the 3-level model(Y is binary variable): Logit(Pijk)=(a0+b0k+c0jk)+b1*X1+b2*X2 i-individual, first level; j-school, 2nd level; k-district,3rd level. I know that the GLIMMIX procedure in the latest version SAS9.2 is a choice for that, but unfortunately we donot have the latest version. R must have the similar functions to do that, can anybody give me some suggestions or help on analysing my dataset? Q1: Which package/functions is appropriate for my task? Could u sho...

Hi. I'm trying to perform what should be a reasonably basic analysis of some spatial presence/absence data but am somewhat overwhelmed by the options available and could do with a helpful pointer. My researches so far indicate that if my data were normal, I would simply use gls() (in nlme) and one of the various corSpatial functions (eg. corSpher() to be analagous to similar analysis in SAS)

I'm estimating two models for data with n = 179 with four clusters (21, 70, 36, and 52) named siteid. I'm estimating a logistic regression model with random intercept and another version with random intercept and random slope for one of the independent variables. fit.1 <- lmer(glaucoma~(1|siteid)+x1 +x2,family=binomial,data=set1,method="ML",

I'd like to estimate an ordinal logistic regression with a random effect for a grouping variable. I do not find a pre-packaged algorithm for this. I've found methods glmmML (package: glmmML) and lmer (package: lme4) both work fine with dichotomous dependent variables. I'd like a model similar to polr (package: MASS) or lrm (package: Design) that allows random effects. I was

Hi, This is not meant to be critical of R, but is intended as a possible source for improvements to R. SAS needs the competition. I am reasonably knowledgeable about R SAS-(all products including IML) SAS and R run on Windows(all flavors) UNIX(all flavors) Apple OSs Does R run on natively (no emulation)? We have quite a few users on these systems VAX-VMS Z-OS (mainframe) MVS VM/CMS(IBM)

...fferent level, > district,school,individual, so this was regarded as a multilevel dataset. > I hope to fit the 3-level model(Y is binary variable): > Logit(Pijk)=(a0+b0k+c0jk)+b1*X1+b2*X2 > i-individual, first level; j-school, 2nd level; k-district,3rd level. > I know that the GLIMMIX procedure in the latest version SAS9.2 is a choice > for that, but unfortunately we donot have the latest version. > R must have the similar functions to do that, can anybody give me some > suggestions or help on analysing my dataset? > Q1: Which package/functions is appropriate for m...