[R-meta] Inverting negative correlations

Dr. Gerta Rücker ruecker @end|ng |rom |mb|@un|-|re|burg@de
Wed Jan 6 20:06:17 CET 2021

Dear David,

Yes, this is correct because

Cov(X,-Y) = - Cov(X,Y)

and the same holds for the correlations.

It is important that the wording is correct. For your example, the 
interpretation would be that if there is a negative correlation between 
social anxiety and extraversion, there is a positive correlation between 
social anxiety and intraversion.



Am 06.01.2021 um 19:50 schrieb david detullio:
> Hello all, I want to include correlation coefficients in a random-effects
> model for meta-analysis. If the majority of the correlations are positive,
> could I use the absolute values of any negative correlations if such
> correlations would have been positive had one of the measures been reverse
> scored? As an example, say there is a negative correlation between a
> measure for social anxiety and a measure for extraversion. Would it be
> possible to take the absolute value of the correlation under the assumption
> that the correlation would be positive if the measure for extraversion was
> reverse scored? Any answers would be appreciated, and if anyone knows of
> source material that talks about this process, the reference would be
> appreciated as well.
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