Phenotype WGs determine phenotype definitions, identify covariates, and set inclusion/exclusion criteria. But they must also consider the advantages and disadvantages of different analytic approaches, i.e. whether to perform meta-analyses of summary data provided by each study, analyses of pooled individual-level data, or both. If investigators choose to perform meta-analyses of summary data, the WG will need to agree on the subgroup analyses, data format, and analysis method used by each study to produce its summary statistics. Investigators need to address the following points:
