Layered process audit: an example and useful questions
The checklist is signed, but the packing station still uses an old label revision. Build short process checks that expose the mismatch and follow it through to closure.
A layered process audit, or LPA, is a set of short checks of important process controls, carried out by different levels of the organisation. Team leaders, managers and plant leadership participate in verifying how the work is being done.
AIAG's explanation puts attention on critical controls and adherence to the agreed method. It does not make an audit signature proof that the process is right.
Consider a packing station where the audit asks, “Are the correct labels being used?” Every form says yes. The mounted roll is still revision R5, although the approved version for this product is R6.
Start from the control the process needs
For this fictional station, the requirement is specific: product P1 must use approved label revision R6. The current instruction must identify that revision, and superseded rolls must be kept out of the usable-label location.
If nobody has defined which revision is current or who updates the instruction, an audit question cannot supply the missing decision. Start with the agreed standard work and procedure.
Keep the check close to an important failure mechanism. A long list of tidy-bench questions would not necessarily expose the wrong revision.
Layered process audit questions: ask for observable evidence
A short checksheet could include these questions. They are our example checks, not a prescribed CQI-8 template.
| Check | Evidence to observe | Response to a mismatch |
|---|---|---|
| Does the current instruction identify the approved revision for P1? | Controlled instruction and the current revision reference | Resolve the instruction before relying on the check |
| Does the label roll mounted at the station match that revision? | Product identity, roll identity and the approved revision | Apply the defined hold and notify the responsible lead |
| Are superseded rolls excluded from the usable-label location? | Identified locations and stock status | Segregate the affected rolls under the agreed method and check prior use |
“Can the operator show the reference and match this roll to it?” produces more useful evidence than “Does the operator know the procedure?” It also helps distinguish a missing reference from a failure to follow a clear one.
Do not improvise a safety or machine test for an audit. Where a control requires a functional test, use the approved test method and keep test material separate from released output.
What makes the audit layered?
Different organisational levels check the process and whether its controls are supported. They share findings and follow-up rather than leaving Quality to collect every form.
One illustrative schedule might give the team lead a daily check, the area manager a weekly review at the station and plant leadership a monthly check of selected controls and recurring findings. Those frequencies are design choices for this example. The actual arrangement needs to reflect risk, customer requirements and the organisation's operating method.
AIAG's public CQI-8 overview includes process-specific checksheets, roles, findings and management review. A locally invented calendar is not evidence of compliance with the complete guideline.
The higher-level check should expose obstacles the local team cannot fix, such as an uncontrolled revision source or an ineffective replenishment route. Repeating the question more often won't resolve those obstacles on its own.
Follow a failed check beyond the next signature
Finding R5 calls for the station's defined response. Record the affected product, roll, time and evidence. The responsible team assesses which work may be affected and what release or containment action is required.
Replacing the roll can restore the immediate condition. Then investigate how R5 entered the usable location and why the previous checks missed it. The 5 Whys example shows how to test an explanation before selecting corrective action.
Name an owner and due date for the correction. Verify that the instruction, storage and replenishment method agree, then check that the control continues to work. A photograph of a new roll today does not establish what happens on the next shift.
Process audit, inspection and gemba serve different purposes
Product inspection examines an output against acceptance criteria. This process audit checks whether the agreed label control is operating. A gemba walk can explore how the work happens and uncover questions the checklist has missed.
Use each where it helps. Passing an LPA does not eliminate the need for required product inspection, and a gemba conversation should not become a disguised exercise in catching people out.
Track completion of the planned checks, but keep recurring failures and verified closure visible too. If the same revision problem returns every week, the signature count is not enough to judge the system.
For this station, the next review should be able to show the current revision, the mounted roll, what happened to affected work and whether the route that supplied R5 has been corrected.
Sources and example notes
- AIAG: Reduce process nonconformance with layered process audits, Murray Sittsamer, 2021. Short verifications by different organisational levels and attention to critical controls.
- AIAG: CQI-8 public overview, checksheets, responsibilities, findings and management review.
The station, product, revisions, checks and frequencies are fictional. The example uses AIAG’s public guidance; the paid CQI-8 manual was not used to set the schedule.