| Preliminary Hazard Analysis | Additional Risk Reduction | Residual Risk | |||||||||||
| Code | Hazard | Potential Effects | Severity | Potential Causes | Likelihood | Risk | Recommended Action(s) | Who/When | Controls or Design Mitigations | Requirements Document Reference | Verification and Validation References | Revised Likelihood | Revised Risk |
| 1.0 | Inaccurate temperature —reading low | Misdiagnosis: false negative; delayed treatment | 3 | A/D conversion error | 2 | Moderate | Add self-calibration check feature | Electrical engineering | If cal. check fails, "err" flashes on display | 5.1.1.1 | See V&V plan ref. XXXX | 1 | Minor |
| Operator error—removed too quickly | 5 | Major | Add timer alarm to indicate insufficient reading time | Electrical engineering | Timer flashes red LED and beeps when time is sufficient; display flashes "err" if insufficient time | 5.1.1.1 | See V&V plan ref. YYYY | 1 | Minor | ||||
| 2.0 | Sensor probe inserted too far | Ear damage: injury and possible loss of hearing | 4 | Inserted too far during use | 3 | Moderate | Add feature to prevent over insertion;. investigate different size guards for various age (ear size) of patient | Design engineering | Tip designed to prevent over insertion; tips available in infant, small, medium, and adult | 6.2 | See V&V plan ref. ZZZZ | 1 | Minor |
| Note: Not all hazards are shown. Severity and likelihood ratings are based on a scale from 1 to 5. Major risks are considered intolerable and moderate as needing to be reduced ALARP. Requirements references a requirements list numbered in hierarchal order. The V&V references are fictitious. | |||||||||||||
Table V. Sample risk management summary matrix for a digital thermometer intended for home use. The device measures temperature in the ear.