[R-meta] Meta-analysis Hedges g - comparisons with same placebo

Viechtbauer Wolfgang (SP) wolfgang.viechtbauer at maastrichtuniversity.nl
Thu Oct 19 20:42:52 CEST 2017

1) Ni is the total sample size of a study. For multitreatment studies, this is the control group size plus the sizes of the treatment groups.

2) Unfortunately, no. The code given there is specifically for the standardized mean difference (for two or more independent groups). The equations (and hence code) will be different when the outcome measure is the difference between the standardized mean changes for the various groups; I assume you mean something along the lines of:



-----Original Message-----
From: P. Roberto Bakker [mailto:robertobakker at gmail.com] 
Sent: Thursday, 19 October, 2017 19:25
To: Viechtbauer Wolfgang (SP)
Cc: r-sig-meta-analysis at r-project.org
Subject: Re: [R-meta] Meta-analysis Hedges g - comparisons with same placebo

It is a nice code. Thank you. 

Some questons:
1. N1 is not always n1i+n2i - how can I interpret this?

2. I am analysing standardized mean deference change - I suppose I can use the syntax also, correct?

Cheers, Roberto

2017-10-19 10:26 GMT+02:00 Viechtbauer Wolfgang (SP) <wolfgang.viechtbauer at maastrichtuniversity.nl>:
There is also code for computing the covariance among the standardized mean differences in such 'multitreatment' studies here:



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