[R-meta] Correcting Hedges' g vs. Log response ratio in nested studies

On Nov 2, 2023, at 3:04 AM, Viechtbauer, Wolfgang (NP) via R-sig-meta-analysis <r-sig-meta-analysis at r-project.org> wrote:
?Dear Yuhang,

I haven't looked deeply into this, but an immediate thought I have is that for SMDs, you divide by some measure of variability within the groups. If that measure of variability is affected by your study design, then this will also affect the SMD value. On the other hand, this doesn't have any impact on LRRs since they are only the (log-transformed) ratio of the means.

Best,
Wolfgang

-----Original Message-----
From: R-sig-meta-analysis <r-sig-meta-analysis-bounces at r-project.org> On Behalf
Of Yuhang Hu via R-sig-meta-analysis
Sent: Thursday, November 2, 2023 05:42
To: R meta <r-sig-meta-analysis at r-project.org>
Cc: Yuhang Hu <yh342 at nau.edu>
Subject: [R-meta] Correcting Hedges' g vs. Log response ratio in nested studies

Hello All,

I know that when correcting Hedges' g (i.e., bias-corrected SMD, aka "g")
in nested studies, we have to **BOTH** adjust our initial "g" and its
sampling variance "vi_g"
(https://ies.ed.gov/ncee/wwc/Docs/referenceresources/WWC-41-Supplement-
508_09212020.pdf).

But when correcting Log Response Ratios (LRR) in nested studies, we have to
**ONLY** adjust its initial sampling variance "vi_LRR" but not "LRR" itself
(https://stat.ethz.ch/pipermail/r-sig-meta-analysis/2021-October/003486.html).

I wonder why the two methods of correction differ for Hedge's g and LRR?

Thanks,
Yuhang