[R-meta] moderator and adjusted effects
Dear Valeria Comments in-line
On 14/12/2020 17:13, Valeria Ivaniushina wrote:
Dear experts, In my sample of articles for meta-analysis there are three categories, or three conditions, that may influence the effect of interest. I am more interested in estimating different effects from these conditions than in explaining heterogeneity in effect sizes. 1) I can do a meta-analysis for each of these conditions separately and get three different mean effect sizes. 2) Or I can do a meta-analysis of the whole sample, then include a condition as a moderator and calculate adjusted effects as described here : http://www.metafor-project.org/doku.php/tips:computing_adjusted_effects
I would go for option two as it will give you estimates of the differences between the levels of your moderator.
Which option is better? Additional question: when I include a categorical moderator, is it the same as including a dummy variable in a regression? How can I specify that the variable is categorical with 3 levels?
If you make the moderator a factor then R will take care of this for you.
Best, Valeria [[alternative HTML version deleted]]
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