[R-meta] Can we call moderators in subgroup analysis predictors?

[Dylan Johnson]

Hello Simon,

The reviewer in this instance is correct. You are pooling the estimate on the grounds of an exposure -> outcome relationship. If you are include sex, for example, the moderator tells you how the exposure and outcome relation changes by sex. This doesn't tell you whether sex itself is a predictor of the outcome.

Does that make sense?

Best,
Dylan

On Dec. 19, 2020 6:39 p.m., Simon Harmel <sim.harmel using gmail.com> wrote:
EXTERNAL EMAIL:

Thank you Michael. I had the same reaction. So, this was from a reviewer
who mentioned:

"You say moderators will eventually serve as predictors in a meta-analysis,
are you referring to meta-regression here? Moderators are not used as
predictors in a classic meta-analysis which simply pools all the effects
into a weighted effect size."

 My response was:

". . . In both cases, categorical moderators/predictors act as on-and-off
switches. I always prefer the meta-regression as it reveals the partial
effect of one moderator controlling for other moderators. But again, in my
context it is fine to generally use the term predictor. I think some may
even find the term moderator confusing because in general it may denote
some kind of interactional effect".

Just wanted to make sure I'm not too far off.

Thanks,
Simon

On Sat, Dec 19, 2020 at 4:32 AM Michael Dewey <lists using dewey.myzen.co.uk>
wrote:

> Dear Simon
>
> My immediate thought is, "Yes, why not?" but do you have some deep doubt
> you want to share with us?
>
> Michael
>
> On 18/12/2020 22:51, Simon Harmel wrote:
> > For clarification, I'm only concerned with categorical moderators.
> >
> > Thanks again,
> > Simon
> >
> > On Fri, Dec 18, 2020 at 3:33 PM Simon Harmel <sim.harmel using gmail.com>
> wrote:
> >
> >> Hello All,
> >>
> >> A quick question. In classic meta-analysis, moderators help to form
> groups
> >> of studies and conduct meta analysis separately in each group.
> >>
> >> In meta-regression, moderators are directly predictors of effect size
> in a
> >> regression analysis.
> >>
> >> But, can we still call moderators in classic meta-analysis predictors of
> >> effect size?
> >>
> >> Thank you,
> >> Simon
> >>
> >
> >       [[alternative HTML version deleted]]
> >
> > _______________________________________________
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> >
>
> --
> Michael
> http://www.dewey.myzen.co.uk/home.html
>

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