title: Retrospective studies provide valuable information.
authors.affiliation: Stanford University Medical Centre, Stanford, CA, USA. eriley@stanford.edu.
authors.forename: E
authors.initials: E
authors.lastname: Riley
mesh_terms: D035843:Biomedical Research / Q000379:methods*; D003627:Data Interpretation, Statistical; D006801:Humans; D019990:Perioperative Care / Q000592:standards*