This study will examine the relationship between hospital readmissions within 31 days of a prior hospital discharge and the occurrence of peer review organization (PRO) quality of care screens. Specifically, the study will test several hypotheses to: (1) assess whether patients with a subsequent readmission within 31 days of prior hospital discharge have higher levels of occurrence of the PRO quality screens than patients without a subsequent readmission; (2) examine the relationship between a readmission and the occurrence of the PRO quality screens during the index hospitalization by type of readmission; (3) examine the relationship between the occurrence of the PRO quality screens during the index hospitalization and the length of time between discharge from the index hospitalization and the readmission; and, (4) determine the accuracy of a readmission as a quality of care indicator to potential misclassification errors in the PRO quality screen data. The hypotheses will be tested using existing medical record review data from the Iowa Foundation for medical Care (IFMC), Iowa's peer review organization. For the period April l, 1991 - March 31, 1992, the IFMC reviewed 3,606 Medicare medical/surgical readmissions and 10,689 Medicare hospitalizations without subsequent readmissions. Both descriptive and inferential statistics will be used in the analysis of the data. Statistical tests will use methods for analysis of binary data in which the independent variables are either categorical or continuous. Where appropriate, the results will be reported in-terms of odds ratios as well as significance tests. The effect of potential errors in the PRO data will be assessed by simulating different error rates. This study builds on the program of research that has been undertaken by the project investigators to enhance understanding of hospital readmissions. This research has raised a number of questions regarding the use of a readmission as a measure of the quality of care provided during the preceding hospitalization. By conducting a series of analyses using available PRO data to examine the relationship between a readmission and the occurrence of the PRO quality of care screens, the proposed study will take a first step towards understanding the assumed relationships underlying the PRO readmission review mandate; i.e., that there is a relationship between a readmission and quality of care and that the PRO screens are valid and reliable measures of the quality of inpatient care.