title: [Prevalence and incidence. These (almost) unknowns].
abstract: OBJECTIVE
  The purpose of the study is to point out some aspects of the most used terms in epidemiology, that is, erroneously, considered a simple and easy subject, but is often incorrectly applied, even in scientific studies. Sometimes the difficulties encountered in the application of epidemiology are underestimated; before the beginning of every scientific study the authors must be perfectly aware of the differences existing between different terms, even if very small. This for the optimal design of the study, and in order to gather as many data as possible and to draw correct conclusions for the readers and for other investigators.
  
  
  METHODS
  The author reviewed indexed journals of Anesthesia of the last ten years looking for studies where epidemiological terms have been used, in order to better evaluate how frequently they occurred and if in the proper way.
  
  
  CONCLUSIONS
  Sometime in the scientific literature these concepts are wrongly used, and this can be a source of incorrect data for both the reader and other investigators. Properly applied epidemiological concepts enhance the validity of the reported data and constitute a solid base of the paper itself.
authors.affiliation: Servizio di Epidemiologia Clinica e Biometria, IRCCS, Policlinico S. Matteo, Pavia.
authors.forename: D
authors.initials: D
authors.lastname: De Amici
mesh_terms: D000758:Anesthesia; D015994:Incidence; D015995:Prevalence
vernacular_title: Prevalenza e incidenza. Queste (quasi) sconosciute.