Last Updated on September 25, 2025 by Melissa Lazaro

Navigating Witness Audits: What Assessors Look For

You’ve prepared your documents. You’ve trained your team. Your PT scheme is up and running. And then—here comes the witness audit.

Suddenly, an assessor is standing in the room or watching your team via screen share, observing every step. The pressure kicks in.

In my experience helping labs through ISO/IEC 17043 assessments, I’ve found that witness audits aren’t scary because of what you do—they’re scary because of how closely someone else is watching.

So let’s cut the anxiety. In this article, I’ll break down exactly what witness audits are, what assessors actually look for, how to prepare your team, and how to show competence without over-explaining or freezing up.

What Is a Witness Audit and Why It Matters

A witness audit is when an accreditation assessor observes your PT team performing real activities in real time. It’s not about reviewing forms or policies. It’s about proving that what’s written in your SOPs actually happens in practice.

These audits often happen during:

• Initial accreditation
• Re-accreditation
• Expansion of scope
• Routine surveillance

Why it matters:
The assessor is confirming that your team is competent, your system works, and your PT activities follow your documented procedures. That real-time visibility builds confidence—and it’s often a key requirement for ISO/IEC 17043:2023 compliance.

What Assessors Typically Observe During a Witness Audit

Every witness audit is different, but here’s what assessors most commonly want to see:

PT Scheme Activities

• Preparation or packaging of PT items
• Homogeneity and stability testing setup
• Statistical evaluation or data analysis
• Software/data entry or results processing

Staff Behavior

• How personnel follow SOPs
• Whether they ask for clarification or improvise
• Confidence and understanding of assigned tasks

Recordkeeping and Traceability

• Logging of data in real time
• Labels, forms, and records used during the task
• Access to and use of controlled documents

Real-world example:
I once supported a provider whose PT item labeling was consistent, but they didn’t have any on-the-spot traceability logs during repackaging. That small gap led to a minor nonconformity—not because they did something wrong, but because they couldn’t prove traceability in real time.

How to Prepare Your Team and Systems

You can’t fake a good system—but you can absolutely rehearse one. Preparation reduces stress and improves consistency. Here’s how:

1. Brief the Right Staff

Select who will be observed and walk them through:

• What activity the assessor will see
• What documents or forms they’ll use
• Where the relevant SOPs are stored
• How to answer questions with documentation

2. Review Key Procedures

Focus on the SOPs that guide the activity being witnessed. Is the version current? Do staff know where it’s stored? Has the team followed it before?

3. Prepare the Physical or Digital Environment

Make sure:

• Forms and logs are accessible
• Equipment is calibrated and labeled
• Work areas are clean and organized
• Communication between team members reflects clear roles

Pro tip: Run a “mock witness audit” a few days before the real one. It doesn’t have to be formal—just have someone observe the activity and ask a few assessor-style questions.

What Assessors Expect to See (And What They Don’t Want to See)

What They Look For:

• Staff following procedures as written
• Records filled out as the activity occurs
• No confusion or improvisation
• Controlled documents in use
• Justification of decisions using data, not guesses

What You Should Avoid:

• “Oh, we normally do that but forgot this time”
• “It’s not written down, but we always handle it like this”
• Outdated forms, unsigned records, or unlabeled samples
• Hesitant or contradicting explanations from staff

Remember: The assessor isn’t judging you—they’re validating your system. Mistakes happen. But unawareness or inconsistency raises red flags.

How to Interact with Assessors During the Audit

This is one of the biggest concerns teams have: “What do I say if they ask something I don’t know?”

Here’s the answer: You don’t have to know everything—just know where to find it.

Be direct and show documentation

If they ask, “How do you assign values in this PT scheme?” don’t just explain. Open your planning record. Point to the method and calculations.

Be honest

If something is unclear, say, “Let me pull up the procedure to be sure,” or “Here’s how it’s documented.” This shows control—not confusion.

Avoid improvising

Never guess. If the answer isn’t obvious, defer to documentation or refer the assessor to someone more directly responsible.

Pro Tips for Smoother Witness Audits

• Pro Tip: Never act differently because someone’s watching. Follow your procedure the same way you would without an audit.
• Pro Tip: Have a printed or digital “witness audit prep sheet” outlining who will be observed, what SOPs are in play, and where supporting records are stored.
• Pro Tip: Use signage, versioned documents, and visible labels to guide assessors without needing explanations.
• Pro Tip: Debrief your team right after the audit. Log what went well, where questions were unclear, and how to do better next time.

Common Mistakes That Cause Problems

Assigning nervous or underprepared staff

It’s not a performance. Choose staff who are comfortable with the task—not just available that day.

Trying to impress with over-explanations

This isn’t a university presentation. Stick to what you do and how you show it.

Using undocumented shortcuts

If you deviate from procedure, document it. If it’s undocumented, it’s noncompliant.

Rushing or skipping steps

Slow down and work deliberately. Doing things right is better than doing them fast.

FAQs

Q: Can we ask questions during the audit?
Yes, but keep it relevant. Don’t turn the audit into a training session. Clarify instructions or timing if needed—but let the assessor do the observing.

Q: What if something doesn’t go perfectly?
Be transparent. Document it as you would in your routine process and walk the assessor through the resolution.

Q: How long does a witness audit usually last?
It depends on the activity, but expect anywhere from one to three hours, plus review of related documentation and a short debrief.

A Witness Audit Is Just Your System—Live

The best way to navigate a witness audit is to stop thinking of it as a performance. It’s simply a real-time look into how your system works when no one’s looking.

And if your documentation is solid, your staff are informed, and your procedures match reality—you’re already doing it right.

Want help preparing?
Grab our Witness Audit Readiness Checklist, or schedule a pre-audit walkthrough with your team. We’ll help you work through the details so you can go into your next audit feeling confident—not caught off guard.

Because clarity beats perfection. Every time.