| #Case | Index stay identifier (index stay = eligible for a possible readmission) |
| #Hospital | Hospital identifier |
| #Site | Location of the hospital |
| Year | Year (most recent year in the SQLape_input.txt file, with at least 10% of records) |
| Risk-PD | Risk groups, used to compute expected rates (labels in Excel table) |
| Complexity | 1) 1-3 diagnoses and operation in Categories.txt file |
| 2) More than 3 categories in Categories.txt file |
| AgeClass | 0-45, 46-65, 66-75, 76-85, 85+ in years |
| PD1 | Observed rate (= 1 if premature death, =0 if not) |
| PD0 | Expected rate (see prediction models for more details, benchmark) |
