[R-meta] Confusion about how to use UN structure

[Viechtbauer, Wolfgang (SP)]

Dear Simon,

I don't know and I am not aware of any simulation studies that address this. Therefore, I cannot really make any recommendations.

Best,
Wolfgang

>-----Original Message-----
>From: Simon Harmel [mailto:sim.harmel using gmail.com]
>Sent: Wednesday, 01 September, 2021 21:19
>To: Viechtbauer, Wolfgang (SP)
>Cc: Reza Norouzian; R meta
>Subject: Re: [R-meta] Confusion about how to use UN structure
>
>Dear Wolfgang,
>
>To correct my question, is it acceptable to not estimate the
>correlations (rhos) that are based on too few pairs (i.e., fixing them
>to 0) in a "UN" structure but at least estimate the correlations that
>are based on a large number of pairs?
>
>Or in such a situation, one has to use a simpler structure like "CS"
>or "HCS" and obtain a single rho estimate representing the correlation
>among all the pairs of the levels? (Maybe in this case, such a rho
>will represent the average correlation among all pairs of the levels,
>right?).
>
>This is exactly the situation I'm in now.
>
>Thank you very much,
>Simon