For patients 18 years of age and older, the number of acute inpatient stays during the measurement year that were followed by an unplanned acute readmission for any diagnosis within 30 days and the predicted probability of an acute readmission. Data are reported in the following categories: 1. Count of Index Hospital Stays* (denominator) 2. Count of 30-Day Readmissions (numerator) 3. Average Adjusted Probability of Readmission