AQL vs 100% Inspection: What Small Product Companies Should Use
AQL sampling and 100% inspection answer different questions. Neither method can compensate for vague product requirements, and neither should be chosen only because it sounds more rigorous.
What Is AQL Sampling?
AQL-based inspection uses a defined sampling plan to inspect a subset of a production lot and make an accept/reject decision. The sample size and acceptance numbers depend on the lot size, inspection level, and selected quality limit.
What Is 100% Inspection?
100% inspection means every unit is checked for the defined characteristic. It can be appropriate when the characteristic is critical, inspection is fast and reliable, the consequence of escape is high, or the supplier is under temporary containment.
Why 100% Inspection Is Not Automatically Better
Human inspectors become fatigued, subjective cosmetic standards can drift, tests may be destructive, and some characteristics cannot be economically checked on every unit. Inspection also detects problems after they have been created; it does not replace process control.
When AQL Can Make Sense
- The supplier process is reasonably stable
- The inspection method is clear and repeatable
- The lot is traceable
- The risk of an individual escape is acceptable
- Historical performance supports reduced inspection
When 100% Inspection Can Make Sense
- Critical or safety-related characteristic
- Recent supplier escape or repeated defect
- Controlled shipping / temporary containment
- Very small production lot
- Fast automated test with high detection reliability
The Step That Comes Before Sampling
Before choosing an AQL level or inspection percentage, define what the inspector is supposed to evaluate. The drawing, specification, approved sample, workmanship standard, test method, defect classification, and acceptance criteria have to be clear.
Use Risk and Supplier Performance to Adjust Inspection
Inspection should not stay fixed forever. Strong performance can justify reduced inspection. Repeated failures can trigger tightened inspection, temporary 100% containment, supplier corrective action, or requalification.
Build the Complete Receiving System
Our supplier quality consulting work connects sampling to qualification, risk, inspection plans, Quality Hold, traceability, NCR/SCAR, and supplier performance. The supporting templates are also included in the free Supplier Quality-First QMS.