[R-meta] Adding random effect to SCE models

Farzad Keyhan |@keyh@n|h@ @end|ng |rom gm@||@com
Wed Jul 21 22:42:04 CEST 2021

Dear James (and the List Member),

First of all, what a useful paper (congrats!). My colleagues and I want to
fit separate SCE models to a number of categorical moderators in our
longitudinal studies (data structure is below, note that multiple rows with
the same time indicator are due to multiple treatment groups in each study,
not any additional outcome measures).

In your paper, although you talk about adding random effects per data
particulars, you seem to mainly mean that for your CHE model.

In our SCE models, we want to encode the assumption that the true effect
sizes at different time points are correlated if they come from the study
and the same category (*a bit unsure whether being from the same category
is quite needed*).

(1) Does this assumption make sense given the purpose of the SCE model
that you had in mind?
(2) If yes, what choices of "struct=" would make sense (to be empirically

** mods = ~ mod_cat*time, random = list(~ mod_cat | study, ~ time |
interaction(study,mod_cat)), struct = c("DIAG","???") **

study mod_cat time
1       1             0
1       2             0
1       1             1
1       2             1
2       1             0
2       2             1
3       1             0


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