1 Clinical Trials and Evidence Based Medicine Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine and Biomedical Research Institute, Foundation for Research and Technology-Hellas, Ioannina 45110, Greece. [email protected]
Heterogeneous data are a common problem in meta-analysis. John Ioannidis, Nikolaos Patsopoulos, and Hannah Rothstein show that final synthesis is possible and desirable in most cases