title: Application of variables control charts to risk-adjusted time-ordered healthcare data.
abstract: In a previous article (M. K. Hart, Qual Manag Health Care. 2003;12(1):5-19), the authors presented risk-adjusted control charts applicable for attributes data. The present article discusses a similar class of control charts applicable for variables data that are often skewed. The key feature of these charts is their application of risk-adjusted data in addition to actual performance data. The resulting charts should decrease the occurrence of both type I and type II errors as compared to the unadjusted control charts. This article presents several control charts that vary in the data transformation and combination approaches. Data depicting hospital length of stay following coronary artery bypass graft procedures were used to illustrate the use of transformed and risk-adjusted control charts.
authors.affiliation: College of Business Administration, University of Wisconsin Oshkosh, 800 Algoma Blvd, Oshkosh, WI 54901, USA. hart@uwosh.edu
authors.forename: Marilyn K
authors.initials: MK
authors.lastname: Hart
authors.forename: James W
authors.initials: JW
authors.lastname: Robertson
authors.forename: Robert F
authors.initials: RF
authors.lastname: Hart
authors.forename: Kwan Y
authors.initials: KY
authors.lastname: Lee
mesh_terms: D015986:Confounding Factors, Epidemiologic; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data / Q000639:trends; D010043:Outcome and Process Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012107:Research Design / Q000706:statistics & numerical data; D020379:Risk Adjustment; D013997:Time Factors; D017749:Total Quality Management / Q000379:methods / Q000706:statistics & numerical data*