title: Types of clinical studies. Introduction.
abstract: The best clinical information comes from high-quality studies that seek answers relevant to patients, in samples of patients, with clinically important outcomes and with results applicable to similar patients to those in the studies. In diagnostics, therapy or prognosis, medical decisions will be based on the clinician's individual experience (of patients seen previously by him/her), or on scientific data (from studies done by others in similar patients), or both. What the clinician does is compare the individual characteristics of his/her patient with others seen in the past, or systematically analyzed in clinical studies. In this paper we will define some aspects of clinical practice that need good data from clinical research, describe the relationship between group medicine and individual medicine, and present the types of studies available in the medical literature, on the basis of which we seek to answer day-to-day clinical questions.
authors.affiliation: Centro de Estudos de Medicina Baseada na Evidência, Faculdade de Medicina de Lisboa, Lisboa, Portugal.
authors.forename: António Vaz
authors.initials: AV
authors.lastname: Carneiro
mesh_terms: D002986:Clinical Trials as Topic; D016021:Epidemiologic Studies; D019317:Evidence-Based Medicine; D006801:Humans