FMEA RPN vs Action Priority (AP): How to Calculate
Action Priority (AP) is determined by looking up the combination of Severity (S), Occurrence (O), and Detection (D) in the AIAG-VDA Action Priority table, which returns High, Medium, or Low. It replaces the older Risk Priority Number (RPN = S×O×D).
Step-by-step
- 1
Rate Severity (S)
Rate the severity of the failure effect from 1 (no effect) to 10 (hazardous without warning) using the AIAG-VDA severity table.
- 2
Rate Occurrence (O)
Rate how likely the failure cause is to occur, from 1 (very low) to 10 (very high), considering current prevention controls.
- 3
Rate Detection (D)
Rate how likely current detection controls are to catch the failure before it reaches the customer, from 1 (almost certain detection) to 10 (no detection).
- 4
Look up Action Priority
Find the S/O/D combination in the AIAG-VDA Action Priority table to get High, Medium, or Low — this replaces the old Risk Priority Number (RPN = S×O×D).
- 5
Act on High and Medium first
Prioritize improvement actions for High, then Medium. Low items need action only if justified. Re-rate after actions to confirm the priority dropped.
Why AP replaced RPN
The Risk Priority Number multiplied S × O × D into a single number from 1 to 1000. The problem: very different risk profiles could produce the same RPN, and a high-severity item could be hidden behind a low number. Action Priority instead weights Severity most heavily and uses a fixed table, giving consistent and defensible priorities — which is why AP was adopted in place of RPN.
Frequently asked questions
- What is Action Priority (AP) in FMEA?
- Action Priority is the AIAG-VDA method for prioritizing FMEA risks. Instead of multiplying Severity × Occurrence × Detection into an RPN, it looks up the S/O/D combination in a table that returns High, Medium, or Low.
- Is Action Priority better than RPN?
- AP addresses RPN’s main weakness: very different risks could share the same RPN. AP weights Severity most heavily and gives consistent, defensible priorities, which is why the AIAG-VDA handbook replaced RPN with AP.
- What do High, Medium, and Low mean?
- High means action is needed; Medium means action should be considered; Low means action is optional. The rationale for each decision should be documented regardless of level.
- Does QSA Hub calculate Action Priority automatically?
- Yes. When you enter Severity, Occurrence, and Detection, QSA Hub returns the Action Priority directly from the AIAG-VDA tables, including for FMEA-MSR (S/F/M).
Get Action Priority automatically
QSA Hub computes Action Priority directly from the AIAG-VDA tables as you enter S, O, and D — for DFMEA, PFMEA, and MSR — and exports to standard Excel formats. Free during beta.
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