[R-meta] Which is the way of using "metamean" and the "byvar" function to examine the influence of multiple categorical variable on the mean values

[mark walton]

I have collected data from 300+ studies on microplastic densities in rivers, I would like to investigate how they vary numeric variables (population density, Average GDP, plastic production) and categorical variables (vegetated/non-vegetated, continent, ecoregion, climatic zone).

However, when running "metamean", and using the "byvar" function I can only analyze one variable at a time. Can anyone recommend a mutivariate method so I can look at what factors are driving the microplastic variation?

Thanks


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