title: Quality improvement studies: the need is there but so are the challenges.
authors.forename: H M
authors.initials: HM
authors.lastname: Krumholz
authors.forename: J
authors.initials: J
authors.lastname: Herrin
mesh_terms: D016000:Cluster Analysis; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D019317:Evidence-Based Medicine; D006302:Health Services Research / Q000379:methods* / Q000592:standards*; D006801:Humans; D009664:Norway; D019982:Organizational Case Studies; D011785:Quality Assurance, Health Care; D012107:Research Design / Q000592:standards; D018401:Sample Size; D013997:Time Factors; D014481:United States