Beyond randomised versus observational studies.
Concato
John
J
Clinical Epidemiology Research Center, West Haven Veterans Affairs Medical Center, West Haven, Connecticut, USA.
Horwitz
Ralph I
RI
D015986:Confounding Factors, Epidemiologic; D006801:Humans; D019370:Observation; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012107:Research Design