[R-meta] The effect size of a moderator in a meta-regression

[Angeline Tsui]

Hello all,

I have a question about the effect size of a moderator in a meta-regression.

In my meta-analysis, I used Cohen's d as the effect size, I ran a
meta-regression with a number of moderators (i.e., like a multiple
regression). I recently have received a feedback of a reviewer asking me
specifically how to interpret the magnitude of the effect size of a
significant moderator. In this case, the beta coefficient of this is about
0.19 and the weighted mean effect size of this meta-analysis is fairly low
(around 0.3 but it is significant).

So my question is how to interpret the magnitude of the beta coefficient
here? In the context of a small weighted effect size, it is fairly large,
for example, a unit change of x1 will lead to 0.19 increase in the Cohen's
d (holding all other moderators constant). In terms of percentage, it is a
large increase, approximately 63% increase (i.e., 0.19/0.3). However, in
terms of the "rule of thumb" of Cohen's d size, it is small, as 0.2 is
small Cohen's d.

What do you think? Do you think that I should interpret the size of beta
coefficient in the context of the weighted mean effect size or stick to the
Cohen's d rule of thumb?

Thanks very much and I look forward to receiving your reply.

Best,
Angeline

-- 
Best Regards,
Angeline

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