QUALITY & ACCEPTANCE SAMPLING
Acceptable quality level (AQL)
AQL is a quality level used when designing or selecting an acceptance sampling plan. The plan defines sample selection and the rules for accepting or rejecting a lot.
ACCEPTABLE QUALITY LEVEL IN PRACTICE
- Define the planAgree lot, defect classes and sampling rules.
- Inspect the sampleSelect and test units using the agreed method.
- Decide the dispositionApply the plan and record the outcome.
Use the agreed units, actual records and approved procedures for your operation.
A WORKED EXAMPLE
A sample decision, not a lot guarantee.
For a purely illustrative single-sample plan, suppose the parties agree to inspect 80 units and accept only when no more than two are defective. Finding three means the lot fails that particular rule. This example is not a lookup from an AQL table and is not a recommended plan. Choosing the real sample size and acceptance number requires the applicable scheme, inspection conditions and acceptable risks.
WHAT THIS MEANS FOR YOUR QUOTE
Agree the requirement before comparing quotes
Use the actual shipment, stock and service requirements. Record the billing unit, included work and responsibility for exceptions.
A LITTLE MORE CONTEXT
Questions about Acceptable quality level
Does AQL 2.5 mean every lot may contain 2.5% defects?
No. It is a parameter in a sampling scheme, not a guaranteed lot defect rate or a universal shipping allowance.
Does passing inspection prove every unit is good?
No. Sampling leaves uncertainty about uninspected units.
Can AQL alone tell us how many units to inspect?
No. The applicable sampling scheme and its other inputs are also required.
Source & example notes
NIST: lot acceptance sampling plans.
Sources provide background on the linked topic. Product documentation describes a particular implementation; confirm the rules, contract and procedures that apply to your operation.
Quantities, costs and scenarios are illustrative, not operating targets, approved handling instructions or guarantees. Source guidance reviewed 22 October 2026.
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