# Keep the history behind a trusted check. Explore poka-yoke verification, unavailable checks and authorised exception history, with clear ownership and evidence of restoration. Canonical: https://vieox.com/insights/poka-yoke/verification-and-bypass-history/ Publisher: VIEOX Published: 2026-10-20 Updated: 2026-10-20 ## What should the history of an error-proofing check contain? Keep its identity and intended function, the relevant verification record, the work or period affected by an exception, the responsible authorisation and evidence of restoration. Record the reason and limits of any conclusion. A passing production count cannot show that an unavailable check was functioning. A check earns confidence through an understandable function and an inspectable history. People need to know when it was verified, what the verification covered and whether an exception affected the work they are reviewing. That record should make responsibility clearer without normalising shortcuts. ## Verify the intended function ASQ’s mistake-proofing approach starts with an identified error and the method intended to address it. Verification should therefore relate to that specific purpose. A device being powered or a screen being green is a different observation from evidence that the intended check was assessed successfully. Sources: [1](https://asq.org/quality-resources/mistake-proofing) ## Keep maintenance records useful HSE’s work-equipment guidance calls for suitable maintenance arrangements and up-to-date existing maintenance logs. For a review of an error-proofing device, retain the relevant work reference and the competent person’s recorded findings. State what was checked rather than letting a generic service-complete label stand in for verification. Sources: [2](https://www.hse.gov.uk/work-equipment-machinery/maintenance.htm) ## Make exceptions visible without normalising them If site procedures permit a controlled exception, the record should preserve its scope, reason, responsible authorisation, applicable temporary arrangements and the affected work. The history is a means of accountability. It is not a set of instructions for bypassing a check or an invitation to treat an exception as normal operation. Distinguish the actual period of unavailability from the time someone entered the record. Where either is uncertain, show the uncertainty and identify who will resolve it. Safety functions require their own competent assessment and procedures; a quality exception record cannot grant permission to defeat a safeguard. ## What establishes the return to normal? Hypothetical example: a production period contains an authorised quality-check exception, followed later by a service entry. The review asks whether the service record also includes verification of restoration and who accepted the return to the normal arrangement. It does not infer restoration from the next successful production cycle. The responsible team establishes which work is affected and what assessment or disposition is needed. The record carries the original exception, follow-up and restoration evidence together so another shift can understand the sequence and the remaining questions. ## Use the history to improve the work Look for recurring reasons that a check becomes unavailable or difficult to use. Invite the people who respond to it to explain the circumstances. Review whether the method, equipment care, work instructions or record quality needs attention. Separate a proposed improvement from an approved change. VIEOX can start with one check whose verification or exception history is hard to reconstruct. A useful initial outcome could be a dependable view of the affected period, a clearer follow-up owner or less effort locating restoration evidence. Define that outcome with the people responsible for the work and judge it against the records available. ## Practical starting points - Record the check’s identity, intended function and verification scope. - Preserve the actual exception period and any timing uncertainty. - Keep authorised scope, responsibility and affected work together. - Require a clear record of restoration rather than inferring it from output. - Review recurring exceptions as questions about the work and its support. ## Questions, answered ### Should bypass history be hidden once normal operation resumes? Retain the history according to the organisation’s applicable record policy, with appropriate access. Restoration changes the current condition; it does not erase the context of earlier work. The responsible team should be able to understand both the exception and how it was closed. ### What if the authorisation or restoration evidence is missing? Present the gap explicitly and identify the responsible role for follow-up. Do not manufacture a complete history from nearby events or a later passing result. Decisions about affected work should follow the organisation’s established assessment and authorisation process. ## Sources and further reading - [ASQ — What is Poka-Yoke? Mistake and Error Proofing](https://asq.org/quality-resources/mistake-proofing) - [HSE — Maintenance of work equipment](https://www.hse.gov.uk/work-equipment-machinery/maintenance.htm) ## Related reading - [Poka-yoke: the overview](https://vieox.com/insights/poka-yoke/) - [Error proofing and interlocks](https://vieox.com/insights/poka-yoke/error-proofing-and-interlocks/) - [Quality investigations](https://vieox.com/solutions/quality/) - [Say hello to VIEOX](https://vieox.com/contact/)