Design tool used to assess risk associated with the different ways (modes) that a system can fail, the severity of their effects, and how to mitigate risk # Steps 1. Identify ***modes*** of failure 2. Identify effects of each mode 3. Rate the ***severity*** $S$ of each mode 4. Identify possible root causes for each mode 5. Rate the ***probability of occurrence*** $O$ of each root cause 6. Identify indicators of each root cause 7. Rate ***detectability*** $D$ of each mode/root cause 8. Calculate ***risk priority*** ($S*O*D$) and criticality ($S*O$) 9. Use design to mitigate high-risk or highly critical failures, then re-asses to ensure goals are achieved