title: Reply to Collins and Le Manach.
authors.affiliation: Department of Cardiovascular Surgery, Hospital Clinic, Valencia, Spain antonio@garciavalentin.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Garcia-Valentin
authors.affiliation: Department of Cardiovascular Surgery, Hospital Clinic, University of Barcelona, Barcelona, Spain.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Mestres
keywords: Cardiac surgery; Clinical prediction rule; Prospective studies; Risk; Statistics; Validation studies