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 transfer of materials and information 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 To help prevent confusion, automated systems must ideally lock access to older versions to ensure outdated specifications are not used for building.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.

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.

Recap: Documentation Control & Data Integrity

Parameter	Requirement	Value / Rule	Action
Document Version Control	Use only current released version.	Obsolete versions must be withdrawn immediately upon new revision release.	Lock/remove access to obsolete versions.
Document Accessibility	Documents must be available at point of use.	Displayed directly at the workstation (e.g., station monitor).	Ensure physical/digital access at the work location.
Record Creation (ALCOA+)	Records must be created contemporaneously.	At the exact time of the event; batch signing at shift end is prohibited.	Create record at event occurrence.
Record Correction	Corrections must be traceable and auditable.	Single line strikethrough of error, enter correct value, add initials & date. Do not use white-out/eraser.	Apply correction protocol; void record if protocol not followed.
Record Retention Period	Retain records for defined regulatory/product lifecycle.	Medical/Automotive/Aerospace: Device lifetime + 2 years. Other: 3-5 years or product life + 1 year.	Archive per policy; verify digital backup integrity quarterly.