How to find AQL and LQ levels from Product Risk Assesment Probabilities?

[rharrisherman]

First you cannot simply determine the AQL (don’t, just don’t) or RQL directly from the severity. The organization must determine the maximum defect rates they want to allow based on the market, regulatory requirements, competitive state and financial costs of failures. For example if your competitor has a .001% failure rate on a severity 3 item, I seriously doubt that the organization would allow a 1% failure rate…once the organization has determined the max allowable defect rates that is your RQL or your reliability for conf/reliability formulas. And the FMEA frequency/probability and detection rate have NOTHING to do with it. NOTHING.

Bev would you have any interest in co-authoring or reviewing a more general whitepaper on risk analysis, perhaps building upon your "fresh approach" paper? Our group did a previous paper, but it needs revision. Happy to reimburse and list you as author.

Rick Herman
Conformance1.com
info@conformance1.com

 

[WR.Rachel]

To find your AQL from the risk assessment:

Calculate Total Risk: Multiply the probability of defects (1%) by the probability of non-detection (0.1%). This gives you a total risk of 0.001%.

Set AQL: Based on the severity (temporary harm), start with an AQL of about 1% to 2%.

Convert to LQ: Use ISO tables to find the sample size for your AQL, then set the LQ lower (like 0.65%).

Adjust Sampling: If costs are high, consider increasing AQL slightly or using reduced sampling plans.