title: Costs and getting ethical approval deter doctors from participating in multicentre trials.
authors.forename: S W
authors.initials: SW
authors.lastname: Crooks
authors.forename: S B
authors.initials: SB
authors.lastname: Colman
authors.forename: I A
authors.initials: IA
authors.lastname: Campbell
mesh_terms: D002986:Clinical Trials as Topic; D003365:Costs and Cost Analysis; D026724:Ethical Review; D028744:Ethics Committees, Research; D004992:Ethics, Medical; D006801:Humans; D015337:Multicenter Studies as Topic; D018579:Patient Selection; D035842:Research Subjects; D006113:United Kingdom