AQL is part of a pre-agreed sampling and decision system. It is not a percentage of defects that the buyer promises to tolerate in every shipment.
Understand what a sampling plan can and cannot do
Acceptance sampling uses a defined sample to support a decision about a lot. It does not prove that every unit is defect-free and should not replace process control. The buyer accepts stated statistical risks when choosing a plan.
Use technical or quality expertise to select the governing standard, edition, inspection level, AQL or other parameters appropriate to the product and contract. This article explains the workflow but does not prescribe universal numeric settings.
Define a coherent inspection lot
State purchase order, style, size, color, production period, factory and quantity included. Do not combine materially different products simply to reduce sample size. If colors, constructions or factories carry different risks, stratify or inspect them separately.
Confirm production and packing completion before sampling. Inspectors need access to randomly selected cartons and units across the lot. A sample drawn only from convenient front rows may not represent production.
Freeze the sample plan before results are known
The plan should identify lot size, level, code or sample size, acceptance parameters by defect class and any special tests with separate sample quantities. Agree rounding, resampling and split-lot rules in advance. Do not change the plan after seeing an unfavorable result without documented authority.
Some checks may be performed on all sampled units, while destructive or time-consuming tests use a smaller defined subset. The final inspection checklist helps separate quantity, workmanship, measurement, packaging and function checks.
Classify defects consistently against approved criteria
Define critical, major and minor defect concepts for the specific product, then add illustrated examples where possible. Classification should consider safety, legal compliance, function, saleability and appearance rather than defect size alone.
Train supplier and inspection teams on the same defect library. Record each observed defect, unit, location and class. The defect classification guide provides a framework for resolving borderline cases.
Make and document the lot decision responsibly
Compare counts with the plan's acceptance and rejection rules by class. Also review systemic findings, failed special tests, packing completion and any issue outside the sampling calculation. A numerically acceptable result does not authorize ignoring a serious isolated risk.
Record accept, reject, hold, sort, repair or conditional disposition with owner and evidence. If corrective work occurs, define how it will be verified and whether the lot identity changes. Feed recurring defects back into production control and future inspection planning.
Keep the sampling-plan source, lot calculation and defect counts with the report. A later reviewer should be able to reproduce why the lot passed or failed. If the buyer grants a concession, state the affected quantity, reason, commercial or operational conditions and whether the same defect remains unacceptable on future orders.
Define the lot, plan, defect classes and decision authority before inspection. Keep statistical disposition separate from any serious safety, legal or functional issue that requires immediate escalation.
