title: Why it is important to include unpublished data in systematic reviews.
abstract: It is known that studies with statistically significant results have a higher probability to be published (publication bias). Therefore, studies with no statistically significant differences (or not favoring the investigational drug) may not be found in commonly accessed databases and remain unpublished. Moreover, unpublished data may also refer to information that are not included in study reports published in scientific journals but that may be important to estimate study outcomes. Retrieving unpublished evidence represents a compelling challenge for researchers, and in the present paper we explore how to do it.
authors.affiliation: Section of Psychiatry and Clinical Psychology, Department of Public Health and Community Medicine, University of Verona, Piazzale L.A. Scuro, 10-37134 Verona, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Trespidi
authors.forename: C
authors.initials: C
authors.lastname: Barbui
authors.forename: A
authors.initials: A
authors.lastname: Cipriani
mesh_terms: D022126:Access to Information; D002986:Clinical Trials as Topic; D006801:Humans; D017594:Publication Bias