Last Updated on December 22, 2025 by Melissa Lazaro

Why Data-Analysis & Statistics Reports Matter Under ISO/IEC 17043

Here’s what I’ve noticed over the years.
Most PT providers do the statistics correctly. The problem isn’t the math. It’s how the analysis is documented.

Under ISO/IEC 17043, statistical decisions can’t live only in someone’s spreadsheet or head.
They need to be traceable. Reviewable. Defensible.

Assessors don’t want to re-do your calculations.
They want to understand what you did, why you did it, and whether it was planned and consistent.

This guide focuses on exactly that:

• What an ISO/IEC 17043-compliant data-analysis and statistics report should contain
• How to present results so technical reviewers don’t have to guess
• How to structure a report that supports both audits and internal decision-making

Let’s break it down the way assessors usually read it.

Scope and Purpose of the Data-Analysis & Statistics Report

This section sets the frame.
If it’s unclear, everything that follows feels shaky.

Your report should clearly state:

• Which PT scheme and round the analysis relates to
• The purpose of the statistical analysis
• Whether the report supports participant reporting, internal review, or both

This is important because ISO/IEC 17043 expects separation between planning, analysis, and interpretation.

Pro tip:
Make it obvious that this report documents what was done, not what was intended.

A common mistake is blending scheme planning language into the analysis report.
That confuses reviewers and raises unnecessary questions.

Description of Data Sets and Result Collection Methods

Now we get into the data itself.

Your report should clearly describe:

• How many participants submitted results
• Which results were included
• Which results were excluded—and why
• How data were validated before analysis

Here’s where transparency matters most.

Pro tip:
If you excluded data, explain it clearly and calmly. Assessors don’t mind exclusions. They mind unexplained ones.

One of the fastest ways to lose confidence is removing data without justification.
I’ve seen audits stall simply because exclusions weren’t documented properly.

This section should leave no doubt about what data entered the analysis and why.

Statistical Methods and Models Used for PT Evaluation

This is where technical reviewers slow down.

Your report should describe:

• The statistical model used
• How assigned values were determined
• Any uncertainty considerations
• References to standards or guidance used, where applicable

Here’s the key thing.
You don’t need to prove you’re clever.
You need to prove you’re consistent and justified.

Pro tip:
Explain why a method was chosen, not just what was used.

A common mistake is listing formulas with no explanation.
That works for statisticians—but auditors want context.

If methods changed from previous rounds, say so and explain why. Silence raises more questions than change.

Outlier Detection, Data Treatment, and Robustness Checks

This is one of the most sensitive parts of the report.

ISO/IEC 17043 expects you to define:

• How outliers are identified
• What rules apply to their treatment
• Whether robustness checks were performed

And yes—this should be decided before seeing the results.

Pro tip:
Decision rules documented in advance protect your credibility.

A common pitfall is adjusting outlier treatment after results are visible.
Assessors can usually tell.

I’ve seen well-documented outlier handling turn potential findings into non-issues—simply because the logic was clear and consistent.

Performance Scoring and Evaluation Criteria

Now we connect statistics to performance.

Your report should clearly state:

• Which performance scores were used
• Acceptance limits and criteria
• How performance categories were defined

This matters because participant reports rely on this section.

Pro tip:
Use the same terminology here that appears in participant reports. Consistency matters.

One frequent issue is changing scoring language between rounds or documents.
Participants notice. Auditors notice faster.

Clear, stable evaluation criteria reduce disputes and simplify reviews.

Analysis Results and Summary Statistics

This section presents the outcome—not the story.

Include:

• Key summary statistics
• Distribution characteristics
• Graphs or charts, if they genuinely add clarity

Here’s something worth remembering.
More data doesn’t mean better reporting.

Pro tip:
If a table or graph doesn’t support a decision or conclusion, consider leaving it out.

Assessors usually skim raw outputs and focus on summaries.
Make those summaries easy to follow.

Deviations, Limitations, and Impact on Result Interpretation

This section shows maturity.

ISO/IEC 17043 expects transparency when:

• Planned methods weren’t followed
• Data quality was affected
• Limitations exist in interpretation

This isn’t about admitting failure.
It’s about showing control.

Pro tip:
Clear disclosure builds trust faster than perfect-looking reports.

A common mistake is downplaying deviations or not documenting them at all.
That almost always leads to follow-up questions.

I’ve seen honest limitation statements reduce the severity of audit findings more than once.

Review, Approval, and Technical Authorization of Statistical Reports

Finally, ownership.

Your report must show:

• Who reviewed the analysis
• Who authorized it technically
• When approval occurred

This matters because ISO/IEC 17043 requires competent oversight—not just analysis.

Pro tip:
Independent review doesn’t mean a different department. It means clear separation of roles.

Missing approvals are one of the easiest nonconformities to avoid.
And one of the most common.

FAQs – ISO/IEC 17043 Data-Analysis & Statistics Reports

Is a separate data-analysis report mandatory?
Not explicitly—but statistical decisions and results must be documented and traceable.

Can this report remain internal?
Yes. It supports participant reports and audit evidence but isn’t usually issued externally.

Do statistical methods need to stay identical every round?
No. Changes are allowed—as long as they’re justified and documented.

Conclusion – Using a Structured Statistics Report Template to Strengthen ISO/IEC 17043 Compliance

A good data-analysis and statistics report doesn’t impress with complexity.
It builds confidence through clarity.

From real audit experience, one thing is consistent.
When statistical decisions are well-documented, assessors move on quickly.

Your next step is simple.
Adopt a consistent data-analysis and statistics report template—and use it every round.