title: Observational studies and randomized trials.
authors.forename: R
authors.initials: R
authors.lastname: Kunz
authors.forename: K S
authors.initials: KS
authors.lastname: Khan
authors.forename: H H
authors.initials: HH
authors.lastname: Neumayer
mesh_terms: D015982:Bias; D016022:Case-Control Studies; D015331:Cohort Studies; D006801:Humans; D015201:Meta-Analysis as Topic; D016032:Randomized Controlled Trials as Topic; D012107:Research Design