By Jasmin Dhakaan Accreditation Expert | The Conformity Edge – ISO/IEC 17000 Weekly Series
The Challenge: Measurement Uncertainty Can Be a Barrier
In accredited laboratories, especially those operating under ISO/IEC 17025:2017, the requirement to evaluate and report measurement uncertainty is not optional it is central to demonstrating technical competence.
However, many lab managers without a technical or statistical background find themselves stuck:
- How much should they understand?
- Are they responsible for uncertainty budgets?
- How can they ensure the lab stays compliant without advanced math or metrology training?
While the responsibility for technical accuracy always lies with qualified personnel, understanding the management side of measurement uncertainty is essential—especially when reporting, guiding teams, making decisions, or facing accreditation audits.
This article offers a practical, standards-aligned overview to help non-technical lab managers confidently support the uncertainty evaluation process, not replace technical roles.
Amira’s Audit Challenge
Consider Amira (a hypothetical character), a lab manager overseeing a pipeline coating test facility in the UAE. She ensures daily operations run smoothly, but when her lab’s ISO/IEC 17025 reassessment arrived, she faced an unexpected challenge.
The assessor asked to review the measurement uncertainty budget for cathodic disbondment testing. The technical staff had prepared it but Amira couldn’t explain the assumptions behind it, nor how it impacted client decisions.
While she was not expected to calculate uncertainty, she realized that as a manager, she needed to understand and oversee the process with clarity especially when it came to:
- Ensuring documentation was audit-ready
- Supporting the team in defining decision rules
- Communicating confidently with clients and assessors
Her situation reflects a growing need in the industry: bridging the gap between technical execution and operational leadership.
What Lab Managers Must Understand
Let’s clarify some core concepts accurately, concisely, and aligned with ISO/IEC 17025.
What Is Measurement Uncertainty?
Measurement uncertainty (MU) is a parameter associated with a result, which characterizes the dispersion of values that could reasonably be attributed to the measurand.
In practical terms:
Result = Measured Value ± Uncertainty
Example:
Coating thickness = 475 µm ± 12 µm (at 95% confidence level, k=2)
This expression does not imply an error but quantifies confidence. ISO/IEC 17025 requires this evaluation only where it is relevant and significant to the validity of results (Clause 7.6.1).
Why Is It Crucial?
- It supports risk-based decisions (Clause 7.8.6.1)
- It informs pass/fail conformity assessments
- It is fundamental to traceability and credibility
- It is required for most calibration results, and many testing scenarios (depending on method and customer requirements)
A Manager’s Role in MU (Without Technical Depth)- The Framework
This 5-step framework enables non-technical lab managers to confidently engage in the uncertainty process within their scope of responsibility without overstepping into areas requiring expert validation.
1. Recognize When MU Is Required to Report
Clause 7.6.1 of ISO/IEC 17025 is clear: not all tests require uncertainty evaluation to report. Managers should ensure MU is evaluated and report when it is relevant to decision-making, traceability, or client reporting.
Typical areas where MU is essential:
- Calibrations
- Quantitative chemical tests
- Dimensional testing
- Environmental monitoring with limits
2. Ensure Identification of Contributing Sources
Common sources of uncertainty include:
Your role: verify that these are identified and documented not to analyze them yourself.
3. Use Validated Tools and Templates
Support your team in using established uncertainty budgets based on:
- Repeated measurements (Type A)
- Specifications, certificates, or past data (Type B)
- Coverage factor (typically k=2 for 95% confidence)
Ensure your team uses verified tools such as:
- Excel-based uncertainty calculators
- GUM (Guide to the Expression of Uncertainty in Measurement) principles
- Software aligned with ILAC G17 and EURACHEM/CITAC guides
Your role: review structure and traceability, not perform statistical calculations.
4. Oversee Decision Rule Application
Clause 7.8.6.1 requires decision rules when reporting conformity. As a manager, you should ensure:
- Decision rules are clearly defined in your SOPs
- The rule applied is communicated to clients
- Risk of false accept/reject is addressed (guard bands, shared risk, etc.)
Your responsibility: ensure consistency and documentation, especially for audits or disputes.
5. Maintain Clear Records and Audit Readiness
A good manager ensures:
- Uncertainty budgets are controlled documents
- Versions are up-to-date and reviewed periodically
- Supporting evidence (certificates, references, validations) is retained
- Staff involved in MU evaluation are competent and records of training are available
This administrative oversight is often what determines success during accreditation.
Bridging the Gap with Leadership Clarity
After adopting this structured approach, Amira no longer felt disconnected from her technical team. She didn’t try to do their job but she:
- Understood how MU impacted reports and decision-making
- Ensured correct templates and rules were in place
- Passed the next audit without findings related to uncertainty
- Gained credibility as a competent leader—not just a manager
This is what ISO/IEC 17025 expects: shared responsibility based on role and competence.
Lab Manager’s Measurement Uncertainty Oversight Checklist
- Understand when MU is required
- Verify identification of MU sources
- Ensure use of validated calculation tools
- Confirm documentation of decision rules
- Maintain up-to-date, traceable records
- Support ongoing technical competence through training and review
Disclaimer
This article is designed to support operational understanding of measurement uncertainty for laboratory managers working within ISO/IEC 17025-accredited environments. It does not replace the responsibilities or authority of qualified technical personnel responsible for the scientific evaluation and validation of uncertainty budgets.
All frameworks and statements are based on internationally recognized guides including ISO/IEC 17025:2017, ILAC P14, ILAC G17, and GUM. The intent is to promote alignment, not oversimplification, and to enhance cross-functional collaboration between managerial and technical roles.
Readers are advised to consult qualified experts or metrology specialists when developing or validating measurement uncertainty models for accreditation or reporting purposes.
