1.2 Documentation control & data integrity

Good documentation serves as the reliable framework for engineering intent. If a production line is operating using Rev A instructions while Rev B is the official released version, non-conforming products are likely to be assembled. Maintaining data integrity ensures that what is believed to be built matches what was actually produced on the floor. Without this integrity, the ability to guarantee product traceability is lost.

The documentation hierarchy

A well-structured QMS organizes instructions by their level of detail. It is important to keep high-level policy separate from granular, step-by-step work instructions so that team members can find the right information easily.

Level 1 (Quality Manual): This is the overarching guide that defines the scope of the quality system and its primary policies.
Level 2 (SOP - Standard Operating Procedure): Procedures outline the workflow, defining who is responsible for handing off tasks to whom (for example, the handoff from Purchasing to Incoming Quality Control).
Level 3 (Work Instructions - WI): These are the visual, step-by-step guides detailing exactly how a localized task is performed by the operator at their station.
Level 4 (Records): Records are permanent snapshots of reality, capturing the evidence that the process was followed, such as specific torque values or test logs.

Quality control & ALCOA+

Principles like the ALCOA+ framework are used to ensure data provides a foundation of verifiable facts, rather than relying on human memory.

Lifecycle Guidelines:

Whenever a document guides a physical action on the floor, it should be readily accessible right at the point of use, such as displayed on a monitor above the assembly station.
When a new revision is released, the previous version needs to be obsoleted immediately. To help prevent confusion, automated systems must ideally lock access to older versions to ensure outdated specifications are not used for building.
Records should always be created at the exact moment the event occurs to maintain accuracy.

Pro-Tip: The practice of batch signing documents at the end of a shift must be avoided. This habit can compromise the accuracy of timestamped data and make failure analysis more difficult if an issue is discovered later. Correction Protocol:

If a handwritten, manual record requires correction, a single strikethrough (~~Error~~) must be used, the correct value written next to it, and initials along with the current date included.
Using white-out or completely erasing data must be avoided, as this obscures the original entry and can cause the entire record to be treated as void during an audit.

Retention & archiving

Ensuring data is safely archived is critical to support future investigations.

Retention Guidelines:

For standard consumer or commercial products, retaining records for 3 to 5 years (or the expected product life plus one year) is typically sufficient.
For specialized products like medical, automotive, or aerospace devices, plan to retain records for the lifetime of the device plus an additional 2 years to satisfy regulatory needs.
Since digital storage is inexpensive, it forms the backbone of modern record-keeping. However, a backup is only useful if it can be restored. Verification of digital backup integrity must be performed quarterly.

Final Checkout: Documentation control & data integrity

Control Point	Critical Requirement	Guiding Principle
Point of Use	Instructions should be easily visible to the operator.	Current documents must be kept accessible, not filed away.
Revision Sync	The production floor must match the engineering master.	Building with outdated revisions creates rework.
Data Entry	Entry should be time-stamped and attributable.	Team members must use their own logins.
Corrections	Single cross-out + initials and date.	The use of white-out or erasures must be prohibited.
Backup	Off-site or cloud redundancy is recommended.	It must be regularly verified that digital backups are intact.