The Meta-analysis OObservational Studies in Epidemiology (MOOSE) guidelines can be used to critically appraise published meta-analyses that include observational studies only.  Observational studies are defined as an etiology or effectiveness studies that use data from an existing database, a cross-sectional study, a case series design, a case-control design, a design with historical controls, or a cohort design.  Meta-analyses using observational studies are controversial because of inherent bias and differences in study designs.  However, this type of meta-analysis is steadily increasing in the published literature and having these guidelines will help you with your critical appraisal.

Article Related to the Guidelines

MOOSE Checklist