CODEWITHSUNDEEP
rlme4
Carmen Franse
Carmen Franse

Reputation: 31

Error using mediation package with lme4 model: mediator model is not yet implemented - previous answer does not work for me

Hi I am new to R and this forum. I have the same problem as a previous poster, but mine was not resolved with the answer. I get the message: "mediator model is not yet implemented" when I try to run a multilevel mediation model using package lme4 and mediation.

My data:

data.frame':    25383 obs. of  115 variables:
$ PID                        : num  1 1 1 1 1 1 1 1 1 1 ...
$ T0_AGE                     : num  66.6 79.7 85.6 87 79.9 67.4 80 72 80.1 
68$ T0_ASEXE                 : Factor w/ 2 levels "Male","Female": 1 1...
$ T0_ALIVING_R               : num  0 0 0 0 1 0 0 0 1 0 ...
$ T0_educationcat            : Factor w/ 3 levels "high","middle",..
$ FI_morbidity_corrected     : num  0.0625 0 0.125 0.0625 0.0625 0.125 ……
$ FI_SRH                     : num  0.5 0.375 0.75 0.625 0.375…."

I am trying to see how FI_morbidity_corrected mediates the relationship between T0_educationcat and FI_SRH. I'm specifying a random intercept for PID (project ID) as data is clustered in different studies/projects. I am controlling for confounders T0_ASEXE + T0_AGE + T0_ALIVING_R

med.fit <- lmer(FI_morbidity_corrected~T0_educationcat + T0_ASEXE + T0_AGE + 
T0_ALIVING_R + (1|PID),data=topicsmds)
out.fit <- lmer(FI_SRH~FI_morbidity_corrected + T0_educationcat + T0_ASEXE + 
T0_AGE + T0_ALIVING_R + (1|PID),data=topicsmds)

This works, but then:

med23.out <- mediate(med.fit, out.fit, treat = "T0_educationcat", mediator = 
"FI_morbidity_corrected", control.value = "high", treat.value = "middle", 
sims = 100)
summary(med23.out)

and

med24.out <- mediate(med.fit, out.fit, treat = "T0_educationcat", mediator = 
"FI_morbidity_corrected", control.value = "high", treat.value = "low", sims 
= 100)
summary(med24.out)

Give me the error:

mediator model is not yet implemented

I have loaded the lme4 pakage using library(lme4) as suggested, but still get this error.

inherits(mediatorModel, "merMod") returned TRUE

getCall(mediatorModel)[[1]] returned lme4::lmer

Thanks!

Upvotes: 3

Views: 4133

Answers (1)

Adam Morris
Adam Morris

Reputation: 303

Are you loading the package lmerTest? If so, class(med.fit[[1]]) returns merModLmerTest instead of lmerMod - but the mediation package expects the latter. Unloading lmerTest would solve the problem.

Upvotes: 11

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