Comparing the Contributions of Groups of Predictors: Which Outcomes Vary with Hospital Rather than Patient Characteristics?

Abstract In a model, such as a logit regression model, we wish to compare the relative importance of two groups of predictors for various objectives. In the example that motivated this work, the model predicts patient outcomes during hospital stays, and we wish to measure the relative contribution of patient and hospital characteristics to the variation in outcomes among patients and among hospitals. This is done using the relative dispersion of patient and hospital contributions to the fitted outcomes. As is seen, this question is distinct from other common questions, including the quality of the overall fit, the degree to which the outcome is accurately predicted, the statistical significance of groups of predictors, and the correlations among and between groups of predictors. Relevant point estimates, confidence intervals, and hypothesis tests are developed. In the example, we examine three outcome measures and find that nearly all of the predictable variation in patient outcomes and most of the predic...

[1]  E. Keeler,et al.  The effects of the DRG-based prospective payment system on quality of care for hospitalized Medicare patients. An introduction to the series. , 1990, JAMA.

[2]  Ker-Chau Li,et al.  Regression Analysis Under Link Violation , 1989 .

[3]  H. Luft,et al.  Evaluating individual hospital quality through outcome statistics. , 1986, JAMA.

[4]  A A Rimm,et al.  Hospital characteristics and mortality rates. , 1989, The New England journal of medicine.

[5]  P. Holland,et al.  Discrete Multivariate Analysis. , 1976 .

[6]  L I Iezzoni,et al.  A clinical assessment of MedisGroups. , 1988, JAMA.

[7]  A. Rosen,et al.  Postoperative Adverse Events of Common Surgical Procedures in the Medicare Population , 1992, Medical care.

[8]  E. Keeler,et al.  The effects of the DRG-based prospective payment system on quality of care for hospitalized medicare patients : Final Report , 1994 .

[9]  L. Iezzoni,et al.  MedisGroups data bases. The impact of data collection guidelines on predicting in-hospital mortality. , 1993, Medical care.

[10]  David R. Cox The analysis of binary data , 1970 .

[11]  Mark A. Moskowitz,et al.  A Clinical Assessment of Medis-Groups , 1988 .

[12]  L. A. Goodman,et al.  Measures of association for cross classifications , 1979 .

[13]  Sankey V. Williams,et al.  Hospital and Patient Characteristics Associated With Death After Surgery: A Study of Adverse Occurrence and Failure to Rescue , 1992, Medical care.

[14]  Frederick Mosteller,et al.  Data Analysis and Regression , 1978 .