Impact of different ‘longer than expected LOS’ thresholds on (1) the proportion of patients selected and (2) the sensitivity and positive predictive value (PPV) associated with detecting a direct indicator of harm
| Threshold | All cases | Longer than expected | Two x longer than expected | Three x longer than expected |
| Acute myocardial infarction | ||||
| % selected (n) | 100 (60 186) | 28 (17 072) | 9 (5664) | 4 (2618) |
| Sensitivity | 100% | 56% | 27% | 15% |
| PPV | 14% | 27% | 40% | 47% |
| Urgent bowel surgery | ||||
| % selected (n) | 100 (3127) | 58 (1806) | 20 (631) | 9 (270) |
| Sensitivity | 100% | 81% | 39% | 19% |
| PPV | 35% | 48% | 66% | 74% |
| Elective bowel surgery | ||||
| % selected (n) | 100 (17 101) | 26 (4420) | 7 (1163) | 3 (468) |
| Sensitivity | 100% | 59% | 21% | 9% |
| PPV | 26% | 60% | 82% | 88% |
| Hip replacement | ||||
| % selected (n) | 100 (52 738) | 31 (16 528) | 5 (2516) | 2 (835) |
| Sensitivity | 100% | 60% | 20% | 8% |
| PPV | 10% | 19% | 41% | 51% |
Hospital Episode Statistics data ©2017, reused with the permission of the Health & Social Care Information Centre. All rights reserved.