Hello. We recently conducted a multilevel meta-analysis. However, it was suggested to perform a hierarchical structure of the meta-analysis to circumvent the issues associated with the existence of different outcomes. That is, we initially conducted the meta-analysis where our outcome variable is aggression. However, it may make sense to specify types of aggression (e.g., physical, psychological, sexual). How is the hierarchical structure of the meta-analysis carried out? Do you know of material that could guide this analysis?

Thanks