[R-sig-ME] Marginal effect plot for an interaction effect from GLMM following a beta-distribution (glmmTMB)

[John Fox]

Dear Jan,

Though I haven't tried it, I believe that the functions in the effects 
package should work with a glmmTMB model of this structure.

Note that you're using the * operator in the model formula incorrectly 
(i.e, redundantly) -- your fixed-effects specification is equivalent to 
ref_turnout ~ contestation + experience_with_ref * unemployment .

I hope this helps,
  John

John Fox, Professor Emeritus
McMaster University
Hamilton, Ontario, Canada
web: https://socialsciences.mcmaster.ca/jfox/

On 2020-10-19 4:21 p.m., Jan anye Velimsky via R-sig-mixed-models wrote:
> 
> Dear R project mixedmodels users,
> 
> I am struggling to estimateand visualize the marginal effects 
> (interaction effect) from a GLMM Model.
> 
> We have been estimatinga GLMM model following a beta-distribution with 
> the glmmTMB-package. The model consistsof factors influencing referendum 
> turnout (range between 0-1) in german municipalities.The primary units 
> of investigation are city districts nested in referendumsnested in cities.
> 
> Here an example model:
> 
> model1 <- glmmTMB (ref_turnout ~ unemployment + contestation+ 
> experience_with_ref + (experience_with_ref *unemployment)+ (1| town/ 
> referendum), family=list(family="beta", link ='logit'), data = ml)
> 
> 
> 
> Results example model:
> 
>                                                                                                    Estimate      Std. Error    zvalue     Pr(>|z|)
> 
> (Intercept)                                         
>                                         -0.583             0.131      -4.455     8.4e-06***
> 
> unemployment                                                            
>              -0.067              0.002      -30.397    < 2e-16 ***
> 
> contestation                        
>                                                       0.008 
>               0.003        2.398     0.0165 *
> 
> experience_with_ref                                                               0.012 
>               0.052       0.228      0.8200
> 
> unemployment: experience_with_ref                                 
> -0.001             0.001      -1.725      0.0845 .
> 
> 
> 
> The model contains an interaction effect with unemploymentper district 
> and experience with referendums in the respective city.
> 
> The aim is to visualize the interaction effects plotting the marginal 
> effects.
> 
> With the "marginal_effects" command from the (margins-package) it was 
> possible to estimate marginal effects,but no further summaries which are 
> needed for plotting the model.  The "margins" command does not work for 
> the glmmTMBmodel.  The idea is to have a simplemarginal effects plot for 
> the interaction effect like this:
> 
> 
> Thanks a lot for your help!
> Jan Velimsky
> 
> -- Jan Velimsky, MAResearch associate
> Ludwig-Maximilians-Universität Munich
> Geschwister-Scholl-Institut of Political Science (GSI)
> Oettingenstrasse 67
> D-80538 Munich
> 
> 
> 
> 
> 
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