[R-meta] Guidance for interpreting fixed effects in multilevel models

[Simon Harmel]

A typo correction:

Model 1: rma.mv(yi ~ 0 + time + ktype + treat, random = list(~ ktype |
study, ~time | interaction(study, group, outcome), ~1 | esID),struct =
c("HCS","HAR"))

On Sun, Aug 8, 2021 at 10:12 PM Simon Harmel <sim.harmel using gmail.com> wrote:

> Dear Colleagues,
>
> I want to use two multilevel meta-regression models (below), but was
> wondering what the correct interpretation of my fixed effects in each one
> is? (given that the models' random effects are different).
>
> In both models, *time* is a factor ranging from 0 to 4;  *ktype* is a
> factor (0=direct,1=indirect) that can vary between studies and between
> groups in each study (but not between outcomes and time points nested
> within those groups in each study);  and *treat* is a study-level
> continuous variable (# of treatments in each study).
>
> Model 1: rma.mv(yi ~ 0 + time + ktype + treat, random = list(~ ktype |
> study, ~time | interaction(study, group, outcome), ~1 | esID),struct =
> c("HAR","HAR"))
>
> Model 2: rma.mv(yi ~ 0 + time + ktype + treat, random =  list(~ ktype |
> interaction(study,group,outcome), ~time | study, ~1 | esID), struct =
> c("UN","UN"))
>
> I highly appreciate your expertise and assistance,
> Simon
>

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