D3 containment evidence checklist: what a reviewer expects to see

A D3 section is often rejected not because containment was missing, but because nothing in the report proves it happened. “All stock sorted, no further issues” is a status, not evidence. This page is a checklist of the records a customer quality engineer commonly expects to see behind each D3 claim. Requirements differ by customer, so check the supplier manual too. For what counts as containment versus a permanent fix, see 8D corrective action vs containment ; for example actions to choose from, see 8D containment actions examples .

Evidence 1: a quantity ledger for every location

One table, one row per location, filled for every place suspect product could be: your plant (WIP and finished goods), your warehouse, in transit, the customer’s stock, and the field or end users where relevant. Each row needs four numbers, not one.

• Quantity suspect (from shipping and stock records for the suspect lots or dates)
• Quantity checked
• Quantity found NOK
• Quantity still open, with the reason
• A location marked “not affected” with the record that shows why, for example the last shipment date or lot list

A reviewer checks that the numbers add up: suspect = checked + open. If the ledger only shows NOK counts, it can’t show that nothing was missed.

Evidence 2: the sort method and its own detection capability

• Which characteristic was checked, with which method, gauge or fixture, and the acceptance criterion
• Proof the method can find the defect: a challenge with known bad parts, boundary samples, or a gauge suited to the tolerance
• Who sorted (your team, the customer, or a sorting service) and the work instruction they used
• For visual checks: lighting, magnification, and the limit sample used

Zero NOK from a method that was never challenged is weak evidence. Record the challenge result next to the sort result.

Evidence 3: the clean point and how it is marked

• The first good lot, date code, serial or production time, as a value the customer can look up
• Why that point is clean: the fix or added check in place from then, with its date
• How known-good parts are marked on the label or packaging, and a photo of the marking
• How many shipments carried the marking before the 8D was sent

Evidence 4: results records you can attach

• Sort sheets per location with date, shift, quantity and result
• Added inspection records, shift by shift, for the period containment runs
• NOK parts: tagged, segregated and held for D4 analysis, with their location
• Photos or measurement data of a sample of NOK parts

Evidence 5: an owner and dates for each action

Every containment row names one owner (a person or role, not “Quality”), the start date, and the planned review date. Missing owners and open-ended dates are common reasons for a Conditional or Reject outcome from the customer.

Evidence 6: the exit criteria for ending containment

• The condition for stopping, written before you stop: for example, the permanent action is verified in D6 and a defined number of lots after it passed the added check
• Who agrees to end it, if the customer must be told or must agree
• The date it ended and the last record of the added check

See D6 verification of effectiveness for the data that usually supports removing containment.

Before you send: a quick D3 self-check

• Can a reader find every location in one table, with numbers that add up?
• Is there one record that shows the sort method finds the defect?
• Is the clean point a value the customer can look up in their own stock?
• Does every action have an owner, a start date and a review date?
• Is the condition for ending containment written down?

If any answer is no, add the record or say when it will follow. A dated gap is easier to accept than a missing one.

Illustrative examples from different sectors

These examples are fictional. Replace every value with your own records.

• Automotive stamping: suspect 4,800 brackets across plant, warehouse, two trucks and the customer; ledger shows 4,800 checked, 37 NOK; height gauge challenged with 5 known bad parts, 5 of 5 found; clean point lot 2841, green dot on label.
• Electronics (PCBA): suspect boards located by serial range; AOI program changed and challenged with seeded defect boards; boards already in the field listed separately, with the customer deciding on field action.
• Medical device components: suspect lots placed on quality hold in the ERP, with a screenshot of the hold status; full dimensional check with records per lot; exit criterion agreed in writing.
• Food packaging: seal-strength test on retained samples per production hour; pallets in the customer’s warehouse labelled and quarantined by pallet ID.

Want a one-page list for the whole report? The free printable 8D / D4 checklist (PDF) covers D1–D8. The free 8D checklist page explains each check.

FAQ

Is this a list of containment actions?

No. For actions to choose from, see the containment actions examples page. This page lists the evidence that shows the actions happened and worked.

When can containment end?

Usually after the permanent action is verified and the agreed exit criteria are met. Some customers require notice or agreement first, so check their requirements.

What does 8D Gate check?

It gives a pre-send readiness check on the 8D text: an Accept / Conditional / Reject advisory with missing evidence and questions. It isn’t a customer decision. The review tool is v0.1: it reviews English 8D reports, and the interface and report are in English. Templates are also available in German, Czech and Polish.

Free pre-send readiness check

Before the 8D goes out, run the text through the free supplier 8D readiness check.

Get the free 8D / D4 checklist

Keep the one-page version ready for the next complaint. It covers D1–D8 and goes deeper on containment, D4 root cause, and verification.