[R-meta] Clarification on ranef.rma.mv()

[Luke Martinez]

Dear Wolfgang and List Members,

In ordinary multilevel models (lmer), one can use ranef() of a model
to get the correlations from the conditional modes of the random
effects (https://stats.stackexchange.com/q/153253/124093) which may
reveal how much random-effects for slopes and intercepts are roughly
correlated.

Similarly, for a struct = "UN" model, I was wondering if
"ranef.rma.mv(fitted_model)" could reveal how much random-effects for
outcome levels are roughly correlated?

For example, for the "res.mv" model below where the REML rho estimate
is "0.775", can ranef.rma.mv(res.mv) values give a rough estimate of
this correlation conditional on the observed data?

dat <- dat.berkey1998
res.mv <- rma.mv(yi~ outcome - 1, vi, data = dat, random = ~ outcome |
trial, struct = "UN")

ran.mv <- ranef.rma.mv(res.mv)

Thank you very much for your help,
Luke