[Mediation-information] Error message for models fitted with lmer: Mediator model not yet implemented?

[Kentaro Hirose]

Hi Hause,

The error message "mediator model is not yet implemented" appears when the
lmer model is not estimated properly. Can you check if (1)
inherits(mediatorModel, "merMod") returns TRUE and (2)
getCall(mediatorModel)[[1]] returns lmer?

It might be also helpful to compare your model with the following toy
example as a way to figure out the problem (e.g., data, code, etc):

-----------------------
library(mediation)
library(lme4)

mediatorModel <- lmer(depress1 ~ treat + age + (1|job_disc), data = jobs)
outcomeModel <- lmer(econ_hard ~ depress1 + treat + age + (1|job_disc),
data = jobs)

mediation <- mediate(model.m = mediatorModel, model.y = outcomeModel, sims
= 100, robustSE = F, treat = "treat", mediator = "depress1")
summary(mediation)
-----------------------

Best,
Kentaro




2016-08-16 1:53 GMT+09:00 Hause Lin <hause.lin at mail.utoronto.ca>:

> Hi,
>
> I've previously used this package to fit simple linear models and it
> worked very well. But recently I've been trying to do this with multilevel
> models (lmer) and I'm getting this message:
>
> Error in mediation::mediate(model.m = mediatorModel, model.y =
> outcomeModel,  :
>   mediator model is not yet implemented
>
> Below are my models. Can anyone tell why I'm getting that error message?
>
> mediatorModel <- lmer(m ~ x1 + x2 + (1 | id), data = df)
>
> outcomeModel <- lmer(y ~ m + x1 + x2 + (1 | id), data = df)
>
> mediation <- mediate(model.m = mediatorModel, model.y = outcomeModel, sims
> = 100, robustSE = F, treat = "x2", mediator = "m")
>
> I really appreciate any help anyone can provide. Thanks!
>
> Best,
> Hause
>
>
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