The default regime
The standard plan as long as quality is compliant but without enough history to streamline.
Sampling · Quality control
AQL applied to the batch record.
"Inspecting less" can't be improvised: it takes a standardized, auditable framework. The AQL (acceptable quality level) is one: it sizes the sampling and lets the inspection breathe — reduced when the history is good, tightened when it degrades. Enough to streamline the batch record at the right level of risk, without giving anything up on compliance.
Normal · Reduced · Tightened
The three AQL regimes: inspection adjusts automatically to the quality demonstrated over time, instead of staying frozen.
The AQL defines, for a given lot size and target quality level, how many units to draw and the acceptance / rejection threshold (Ac/Re). Its strength: switching rules. A compliant history switches you to reduced inspection (you draw fewer units); a degradation triggers tightened inspection. Inspection becomes proportionate and self-regulating — exactly what you want to streamline a batch record without losing control.
The real problem
Frozen sampling never rewards quality.
When the sample size and frequency never change, an exemplary supplier or process is inspected exactly like a poor one. It's discouraging, costly and has no risk logic. AQL fixes this: it ties the inspection effort to the performance actually demonstrated, in both directions.
How it works
Three regimes, switching rules.
The reward for consistency
After a series of compliant lots, you draw fewer units: this is where the workload reduction is won.
The safety net
As soon as quality degrades, you automatically tighten up. Streamlining is never a one-way street.
For each plan: a sample size and an acceptance / rejection pair (Ac/Re). The switch between regimes follows rules defined in advance — that's what makes the streamlining defensible in an inspection.
To the batch record
From the AQL principle to real frequency.
AQL applies above all to attribute inspection (compliant / non-compliant). Used well, it structures the streamlining.
Tie it to real risk
The regime (normal / reduced / tightened) follows from the deviation history and criticality — not from an arbitrary decision.
Document the switch
The rules for moving from one regime to another are written into the procedure: traceable and auditable.
Combine with variable inspection
For measured parameters (weight, volume…), AQL is complemented by process capability (Cpk) and history.
Plan for the rollback
A degradation criterion immediately brings you back to the higher regime: streamlining stays under control.
Frequently asked questions
AQL, in plain terms.
The AQL (acceptable quality level) is the level of defects deemed acceptable for a lot. It underpins sampling plans (ISO 2859 standard for attribute inspection): for a given lot size, it sets the sample size and the acceptance / rejection threshold (Ac/Re).
These are the three AQL regimes. Normal inspection is the default regime; reduced inspection draws fewer units after a series of compliant lots; tightened inspection ratchets up as soon as quality degrades. Predefined switching rules move you from one to another.
Yes: switching to reduced inspection is precisely the mechanism that reduces the workload, while keeping a safety net (return to tightened). It's a standardized framework, and therefore defensible in an inspection, provided you document the switching rules and the link to the quality history.
In practice, yes: AQL structures attribute inspection (compliant / non-compliant), while process capability (Cpk) and history justify streamlining inspection on measured parameters (weight, volume…). The two combine within an overall approach.
Let your controls breathe.
Let's structure your AQL sampling plans to streamline at the right level of risk, with documented switching rules.