[R-meta] Question on funnel plot interpretation

[Viechtbauer, Wolfgang (NP)]

Just to add this:

With such high heterogeneity, there is (IMHO) no point in using the regression test to examine the data for funnel plot asymmetry / publication bias / small study effects. The heterogeneity then 'overwhelms' the sampling variances, so the kinds of patterns we might want to detect via this (and related) methods are just not going to be there or are due to undetected moderators (which could lead to rather misleading conclusions about the potential presence of publication bias).

Best,
Wolfgang

>-----Original Message-----
>From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-bounces using r-project.org] On
>Behalf Of Michael Dewey via R-sig-meta-analysis
>Sent: Wednesday, 05 July, 2023 14:10
>To: Gabriel Cotlier; Yefeng Yang
>Cc: Michael Dewey; R Special Interest Group for Meta-Analysis
>Subject: Re: [R-meta] Question on funnel plot interpretation
>
>Dear Gabriel
>
>Before you continue searching for small study effects I think a search
>for possible moderators of the effects would be more worthwhile. If you
>believe that the purpose of meta-analysis is to synthesise then the
>spread of values you have calls that goal into question. If you believ
>that the purpose of meta-analysis is to understand why effects differ
>then searching for possible moderators must be more helpful than looking
>for small study efects.
>
>Michael
>
>On 05/07/2023 12:31, Gabriel Cotlier wrote:
>>
>> Ok, so in my case would it be better  to use for instance either inverse
>> n or alternatively variance,  is this correct?
>>
>> Regarding the high variability in the range of my Fisher's z transformed
>> values you noticed before.
>> This variability could be due to the fact that the values come
>> from different geographies, use of varied treatments and
>> different methods as well?
>> Is there a quantitative measure or way that can help to give account of
>> such variability or explain it?
>>
>> Thanks a lot again for your advice and guidance.
>> Kind regards,
>> Gabriel