title: [Experimental efficacy versus observational efficacy].
authors.affiliation: Dipartimento di Epidemiologia ASL RME, Via di Santa Costanza, 53, 00198 Roma.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Perucci
authors.forename: Marina
authors.initials: M
authors.lastname: Davoli
mesh_terms: D001290:Attitude; D019317:Evidence-Based Medicine; D006801:Humans; D019370:Observation