A process FMEA, short for failure mode and effects analysis, is a structured way to list what can go wrong at each step of a process before it does. It rests on three linked ideas. The failure mode is the specific way the step can fail to do its job. The effect is what happens downstream, to the next operation, the product, or the end user, if that failure occurs. The cause is the reason the failure mode happens in the first place.
Teams mix these up constantly, and the mix-up matters because each one is treated differently later. You score severity on the effect, occurrence on the cause, and detection on your ability to catch the mode or the cause. If the three are muddled, the scores are muddled too.
A quick test helps. For each item, decide whether it is the thing that went wrong (mode), the consequence of it (effect), or the reason behind it (cause). Write them in three separate columns and do not move on until each row reads cleanly.
Standard Procedure
- 1Write the purpose of the process step in one sentence.
- 2List each way the step could fail to meet that purpose; these are the failure modes.
- 3For each mode, describe the effect on the next operation and on the end user.
- 4For each mode, name the specific, physical cause, not a vague label like "operator error".
- 5Read each row aloud as "because [cause], [mode] happens, which leads to [effect]" and fix any row that does not make sense.
Lesson Summary
- ✓Mode, effect, and cause answer three different questions and get three different scores.
- ✓Vague causes produce vague actions; push for the physical mechanism.