title: [Clinical research I. The importance of the research design].
abstract: The endeavor of clinical research to study a group of patients is to make a diagnosis, estimate the prognosis and prove a treatment. For this purpose is used the scientific method: 1) the architectural arrangement, which can be divided into cause-effect and the process of research; 2) the methodological approach, which includes controlled clinical trials, cohorts, case control, and cross-sectional designs; 3) the goal-oriented approach, in which studies on diagnostic tests, prognosis, treatment and risk or causal factors are grouped. The designs mentioned above are considered primary studies; it means that the information was obtained directly from the subjects studied. There is a second category of studies, which uses information obtained from the primary studies. This is the reason why they are considered as secondary or integrative studies.
authors.affiliation: Centro de Adiestramiento en Investigación Clínica, Coordinación de Investigación en Salud, Instituto Mexicano del Seguro Social, Distrito Federal, Mexico. jtalaverap@cis.gob.mx
authors.forename: Juan O
authors.initials: JO
authors.lastname: Talavera
mesh_terms: D035843:Biomedical Research / Q000458:organization & administration* / Q000592:standards*; D006801:Humans; D012107:Research Design / Q000592:standards*