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

[Simon Harmel]

Dear Wolfgang,

Sure, thank you. So, if I alternatively use "HCS" or "CS", what can I
say about the meaning of the single rho that I get, the average
correlation among all pairs of the levels or something else?

Also this single rho won't be negatively affected by the lack of
co-occurrences on some pairs of the levels as was the case with "UN"?

These will be very helpful to know, thanks a lot,
Simon

On Wed, Sep 1, 2021 at 2:48 PM Viechtbauer, Wolfgang (SP)
<wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
>
> 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