How Certification Bodies Classify Minor & Major Nonconformities

Why should you care?

When undergoing an ISO 9001 or AS91xx audit by a Certification Body (CB), if the auditor incorrectly classifies a “minor” nonconformity as a “major”, this typically requires the auditor to return on-site to (1) verify the effectiveness of the corrective action and (2) confirm a return to compliance. This means, in addition to the day rate charged by the CB, your company would have the added Travel & Living expenses of the auditor.

Similarly, if an auditor incorrectly classifies an “Opportunity for Improvement” (OFI) as a “minor” nonconformity, this would require you to initiate a corrective action… and the CB to verify and close the nonconformity (typically performed during the following site visit). While less expensive than a major non-conformity, each incorrectly classified “minor” nonconformity results in unnecessary administrative costs.

If your company is certified to one of the AS91xx standards, minor nonconformances must be included in the OCAP risk calculation… which could result in additional time added to your audits.

You should be aware of the below “official” definitions and challenge the auditors to explain their justification for classifying a:

  • nonconformity as a “Major” instead of a “Minor”, and/or
  • “Minor” nonconformity rather than an “Opportunity for Improvement” (OFI)

Where you disagree over the classification, you should “appeal” the nonconformity based on its classification (i.e., requesting the CB to reclassify the nonconformity).


Source: Before classifying a nonconformity as a minor or major, the auditor must have a clear understanding of their definitions.

Nonconformity classifications are defined in ISO/IEC 17021-1 for both ISO 9001 & AS9100 audits. AS9101 expands these definitions for AS9100 series audits. However, IMO, AS9101 merely clarifies the vague definitions contained in ISO/IEC 17021-1.

Due to the ambiguous/vague nature of many “requirements” contained in ISO 9001 & AS9100, the auditor must be able to justify each nonconformity (which the auditee may appeal to the CB). Due to the auditor's bias toward a particular interpretation of the standard, far too many auditors “imagine” nonconformities where none exist. It is recommended to always refer to the applicable definitions document when interpreting a standard. “Notes”, whether in the terms and definitions section of a standard or in a vocabulary and definitions document, are NOT requirements.

ISO 9001 & AS9100, “Introduction, 0.1 General” (last sentence in section) states:

Information marked as “NOTE” is for guidance in understanding or clarifying the associated requirement.

Minor Nonconformities

ISO/IEC 17021-1 clause 3.13, Minor nonconformity
nonconformity that does not affect the capability of the management system to achieve the intended results.


AS9101F, sec. 3.4 Minor Nonconformity
The requirements of ISO/IEC 17021-1 clause 3.13 apply.
In addition a minor nonconformity can be a single system failure or lapse in conformity to meet a 9100-series standard requirement, customer QMS requirement, or documented information defined by the organization.

In other words, a nonconformity that is NOT likely to result in the delivery of a nonconforming product or service. Examples of minor nonconformities may include: administrative errors in non-deliverable records or procedures, a lapse in following a procedure that did not impact the deliverable product or service, etc.

Major Nonconformities

ISO/IEC 17021-1 clause 3.12, Major nonconformity
nonconformity that affects the capability of the management system to achieve the intended results.

Note 1 to entry: Nonconformities could be classified as major in the following circumstances:
• if there is a significant doubt that effective process control is in place, or that products or services will meet specified requirements;
• a number of minor nonconformities associated with the same requirement or issue could demonstrate a systemic failure and thus constitute a major nonconformity.


AS9101F, sec. 3.3 Major Nonconformity
The requirements of ISO/IEC 17021-1 clause 3.12 apply.
In addition, a major nonconformity can be one or more of the following situations:
• a nonconformity where the effect is judged to be detrimental to the integrity of the product or service;
• the absence of or total breakdown of a system to meet a 9100-series standard requirement, a customer QMS requirement, or documented information defined by the organization;
• any nonconformity that can result in the probable delivery of nonconforming product or service; and
• a condition that can result in the failure or reduce the usability of the product or service and its intended purpose.

As you can see, the threshold for a Major Nonconformance is actually quite low. Consequently, many CBs ask their auditors to provide justification for identifying minor nonconformities that could be interpreted as major nonconformities. This justification should identify any factors mitigating the nonconformity from a major to a minor.

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