title: Making sure that clinical trial results make a difference: operational research and the hierarchy of evidence.
authors: N
authors: N
authors: Ford
authors: D
authors: D
authors: Maher
mesh_terms: D002986:Clinical Trials as Topic / Q000379:methods* / Q000592:standards; D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D009874:Operations Research