Reliability of the redundant units
| Redundant step | Reliability | Birnbaum importance index |
| Verbal handover at Radiology (D1) | 0.07 | 0.32 |
| Written handover (transfer form) at Radiology (D2) | 0.37 | 0.48 |
| Verbal handover at ward (D3) | 0.26 | 0.41 |
| Written handover (transfer form) at ward (D4) | 0.31 | 0.43 |