[R-sig-ME] Questions regarding MODEL AVERAGING output

[Helen McCallin]

Hi

I would like to post the following question to the forum please?


I am running a glmer model on a response variable with binomial distribution and random term. My data has 3 explanatory categorical variables and I have successfully run dredge() on them and their interactions to get AICc values.


I want model averaging to provide output with coefficients and an index of relative importance of fixed effects from those models; within a delta constraint that I specify.I can get this using the code below for alternative datasets but not for this dataset.

This is what I have input.

ae <- read.csv(file=file.choose())

options(na.action="na.fail")

global.model<-glmer(

     cbind(numerator,total-numerator)~d+s+t+d:s:t+d:s+d:t+s:t+(1|random),

     data=ae, family=binomial)

options(max.print=1000000)

dredge(global.model,beta=c("none"),evaluate=TRUE,rank="AICc")

ae.model <- glmer(

     cbind(numerator,total-numerator)~d+s+t+d:s:t+d:s+d:t+s:t+(1|random),

    data=ae,family=binomial)

models <- dredge(ae.model)

summary(model.avg(get.models(models,subset=delta<5)))

model.avg() produces this error message:

Error in model.avg.default(get.models(models, subset = delta < 5)) : models are not unique. Duplicates: '2 = 3 = 4' and '10 = 11'
This doesn't make sense, DREDGE does not (cannot) produce duplicate models � each model is a unique iteration within the full model, yet the error message indicates that MODEL AVERAGE identified �duplicate� models from within DREDGE output. R fails to run MODEL AVERAGE under these circumstances - producing no further output.
Has anyone else experienced similar problem (with 'not unique', duplicate models) via MODEL AVERAGE?
Is there a workaround for the error that prevents me running MODEL AVERAGE due to perceived �duplicate� models in DREDGE?
I am happy to provide Dropbox link to data.

Thanks in advance for any help given. Summary of data below:

summary(ae)

  p                   t           day             hour            scan             random    behaviour

 ae:182   blood        :42   Min.   :1.000   Min.   :1.000   Min.   : 0   ae_blood_1_1:  7   alert:182

          egg          :35   1st Qu.:1.000   1st Qu.:1.000   1st Qu.:10   ae_blood_1_2:  7

          repellentfree:63   Median :2.000   Median :2.000   Median :30   ae_blood_1_3:  7

          wolf         :42   Mean   :1.654   Mean   :1.962   Mean   :30   ae_blood_2_1:  7

                             3rd Qu.:2.000   3rd Qu.:3.000   3rd Qu.:50   ae_blood_2_2:  7

                             Max.   :3.000   Max.   :3.000   Max.   :60   ae_blood_2_3:  7

                                                                          (Other)     :140

   numerator           total      proportion        percentage      d                        s

 Min.   : 0.0000   Min.   :17   Min.   :0.00000   Min.   : 0.000   E :14   1 - very light wind:21

 1st Qu.: 0.0000   1st Qu.:17   1st Qu.:0.00000   1st Qu.: 0.000   SE:84   2 - light wind     :70

 Median : 0.0000   Median :17   Median :0.00000   Median : 0.000   SW:35   3 - moderate wind  :77

 Mean   : 0.5824   Mean   :17   Mean   :0.03426   Mean   : 3.426   W :49   4 - heavy wind     :14

 3rd Qu.: 0.0000   3rd Qu.:17   3rd Qu.:0.00000   3rd Qu.: 0.000

 Max.   :16.0000   Max.   :17   Max.   :0.94118   Max.   :94.118


Many thanks for your help

Helen McCallin

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