[R-meta] Meta-analysis including multiple intervention arms
Thank you, that's what I thought! Best Ioana
On Sat, Nov 14, 2020 at 4:29 PM James Pustejovsky <jepusto at gmail.com> wrote:
The short answer is no. If you are using RVE with a correlated effects working model, the (assumed) correlation between the effect sizes from each intervention arm takes care of the issue. Splitting the control sample size would over-correct, so that the study would end up with less weight than it should receive. James
On Nov 14, 2020, at 8:44 AM, Ioana Cristea <
ioana.alina.cristea at gmail.com> wrote:
?Dear all I am doing a meta-analysis of randomized trials where some trials have multiple outcomes of interest (depression measured with different scales) and a few have more than one active arms, usually 2 intervention arms and control (therapy A compared to control, therapy B compared to control). I am using robust variance estimator. My question is: for the cases where there are multiple active intervention arms in a trial, compared to the same control arm, should I adjust the sample size of the control arm (ie, splitting by 2 if there are 2 active interventions compared to control)? Thank you Ioana -- Ioana-Alina Cristea, Ph.D. Assistant Professor Department of Brain and Behavioral Sciences University of Pavia, Piazza Botta 11, 27100 Pavia, Italy Research affiliate METRICS (Meta-research Innovation Center at Stanford) Stanford University, California, USA Editorial Advisory Board Lancet Psychiatry <https://www.thelancet.com/journals/lanpsy/home> International Editorial Board BJPsych Open <https://www.cambridge.org/core/journals/bjpsych-open> ORCid: http://orcid.org/0000-0002-9854-7076 Publons: https://publons.com/author/1196647/ioana-alina-cristea#profile Researchgate: https://www.researchgate.net/profile/Ioana_Cristea Twitter: https://twitter.com/IoanaA_Cristea [[alternative HTML version deleted]]
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Ioana-Alina Cristea, Ph.D. Assistant Professor Department of Brain and Behavioral Sciences University of Pavia, Piazza Botta 11, 27100 Pavia, Italy Research affiliate METRICS (Meta-research Innovation Center at Stanford) Stanford University, California, USA Editorial Advisory Board Lancet Psychiatry <https://www.thelancet.com/journals/lanpsy/home> International Editorial Board BJPsych Open <https://www.cambridge.org/core/journals/bjpsych-open> ORCid: http://orcid.org/0000-0002-9854-7076 Publons: https://publons.com/author/1196647/ioana-alina-cristea#profile Researchgate: https://www.researchgate.net/profile/Ioana_Cristea Twitter: https://twitter.com/IoanaA_Cristea [[alternative HTML version deleted]]