1.2 Documentation control & data integrity

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

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+

We look to principles like the ALCOA+ framework to ensure our 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prevent confusion, automated systems should ideally lock access to older versions to ensure operators do not build to outdated specifications.
Records should always be created at the exact moment the event occurs to maintain accuracy.

Pro-Tip: Try to avoid the practice of batch signing documents at the end of a shift. 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, simply use a single strikethrough (~~Error~~), write the correct value next to it, and include your initials along with the current date.
Avoid using white-out or completely erasing data, 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. It is good practice to verify your digital backup integrity quarterly.

Final Checkout: Documentation control & data integrity

Control Point	Critical Requirement	Guiding Principle
Point of Use	Instructions should be easily visible to the operator.	Keep current documents 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.	Ensure team members use their own logins.
Corrections	Single cross-out + initials and date.	Refrain from using white-out or erasures.
Backup	Off-site or cloud redundancy is recommended.	Regularly verify that digital backups are intact.