title: Commentary: Systematic reviewers face challenges from varied study designs.
authors.affiliation: Cancer Research UK Medical Statistics Group, Centre for Statistics in Medicine, Institute of Health Sciences, Oxford OX3 7LF. doug.altman@cancer.org.uk
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Altman
mesh_terms: D003627:Data Interpretation, Statistical; D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods* / Q000592:standards; D012107:Research Design; D012196:Review Literature as Topic