Accreditation vs. Certification: Key Distinctions

Accreditation and certification are both formal conformity assessment mechanisms, but they operate at different levels of the quality infrastructure hierarchy and carry distinct legal and regulatory implications. Confusion between the two terms leads to procurement errors, regulatory non-compliance, and misrepresentation of organizational status. This page defines each mechanism precisely, explains how they function structurally, maps the scenarios where each applies, and provides decision criteria for distinguishing between them.

Definition and scope

Certification is a third-party attestation that a product, process, service, management system, or person meets specified requirements — typically a published standard, regulation, or scheme document. A certification body (CB) issues a certificate to the entity seeking conformity recognition. The scope of that certificate is bounded by what was assessed: an organization may hold ISO 9001 certification covering one manufacturing site but not others (see Scope of Certification Boundaries for the boundary mechanics).

Accreditation is a higher-order process. An accreditation body (AB) evaluates and formally recognizes that a certification body, testing laboratory, inspection body, or other conformity assessment body (CAB) is competent to perform specific conformity assessment activities. The International Organization for Standardization defines this distinction in the ISO/IEC 17000 vocabulary standard: accreditation is "third-party attestation related to a conformity assessment body conveying formal demonstration of its competence" (ISO/IEC 17000:2020, §6.10). Certification, by contrast, is addressed in §6.5 of the same document as "third-party attestation related to products, processes, services or systems."

In the United States, the two principal national accreditation bodies are ANAB (ANSI National Accreditation Board) and A2LA (American Association for Laboratory Accreditation), both operating under frameworks aligned with ISO/IEC 17011, which governs accreditation bodies themselves (ISO/IEC 17011:2017). For a full treatment of these bodies and their scope, see ANAB and A2LA Accreditation Bodies.

The scope distinction matters concretely: a manufacturer cannot seek accreditation for its product — it seeks certification. A testing laboratory cannot seek certification for its technical competence under ISO/IEC 17025 — it seeks accreditation.

How it works

The two mechanisms follow parallel but structurally distinct process chains.

Certification process (abbreviated):

1. The applicant organization identifies the applicable standard or scheme (e.g., ISO 9001, ISO 14001, ISO/IEC 27001).
2. A certification body conducts a Stage 1 (documentation review) and Stage 2 (on-site audit) assessment per ISO/IEC 17021-1:2015, which is the core standard governing management system certification bodies.
3. The CB issues a certificate if the audit team finds no unresolved major nonconformities. Details on handling findings appear in Nonconformity Handling in Certification.
4. Surveillance audits occur at defined intervals (typically annually for ISO management system schemes) to verify continued conformity.
5. Re-certification occurs at the end of the certificate cycle, commonly every 3 years for ISO management system standards.

Accreditation process (abbreviated):

1. A conformity assessment body applies to an accreditation body, submitting documentation of its management system, technical competence, and impartiality controls.
2. The AB conducts an office assessment and a witness assessment — the AB's assessors observe the CAB performing actual certification or testing activities.
3. The AB issues an accreditation certificate and a defined scope of accreditation, specifying which standards, methods, or activities the CAB is authorized to perform.
4. Surveillance assessments are performed by the AB, and re-accreditation follows a multi-year cycle, typically 4 years for ISO/IEC 17011 cycles.

The key structural difference: the certification body is simultaneously the assessor (of clients) and the assessed party (under the accreditation body). The accreditation body has no direct relationship with the end organizations seeking certificates — it only evaluates and recognizes the CBs.

Common scenarios

Scenario A — Manufacturing (product certification): A hardware manufacturer requires third-party product certification to the UL 60950-1 safety standard before entering retail channels. UL LLC, operating as a certification body, issues the certificate. UL LLC's competence as a certification and testing body is itself subject to accreditation under ISO/IEC 17065 (product certification bodies) by an AB such as ANAB. The manufacturer holds certification; UL holds accreditation.

Scenario B — Management systems (ISO 9001): A mid-sized contract manufacturer pursues ISO 9001:2015 certification. A CB accredited by ANAB conducts the audit. The manufacturer's certificate references the CB's accreditation, giving downstream customers assurance that the CB met objective competency standards — not merely that the CB exists and issued paper. The Certification Decision Process page details how CBs formalize that final issuance decision.

Scenario C — Personnel certification: An individual earns a professional credential through a personnel certification program (e.g., ASQ Certified Quality Engineer). The certifying organization's program may be accredited by the ANSI/ISO/IEC 17024 pathway through ANAB, signaling that the exam development, administration, and recertification requirements meet international competency standards. The individual holds certification; the certifying organization holds accreditation.

Scenario D — Federal regulatory programs: The National Voluntary Laboratory Accreditation Program (NVLAP), administered by NIST, accredits testing and calibration laboratories for use in federal procurement and regulatory compliance. Laboratories under NVLAP hold accreditation; the products or materials they test may or may not be separately certified (NIST NVLAP).

Decision boundaries

The following classification framework identifies which mechanism applies:

Three boundary questions that resolve ambiguity:

1. Is the subject of assessment a body performing conformity assessment, or an entity/product seeking conformity recognition? If the former, the applicable mechanism is accreditation. If the latter, certification.

2. Does a federal or state regulation specifically require accredited laboratories or accredited CBs? Several EPA, FDA, and OSHA programs mandate that testing or auditing be performed by accredited bodies, not merely certified ones. The distinction is regulatory, not discretionary.

3. Is impartiality independence required at the body level? ISO/IEC 17021-1 and ISO/IEC 17065 impose structural impartiality requirements on CBs. Accreditation bodies assess whether those controls are functioning — they do not assess client organizations directly.

The Regulatory vs. Voluntary Certification page addresses the overlay of regulatory mandates on both mechanisms. For organizations mapping their full conformity assessment obligations, the Compliance Standards Overview provides the foundational framework within which both accreditation and certification operate.

References

• ISO/IEC 17000:2020 — Conformity assessment: Vocabulary and general principles
• ISO/IEC 17011:2017 — Conformity assessment: Requirements for accreditation bodies
• ISO/IEC 17021-1:2015 — Conformity assessment: Requirements for bodies providing audit and certification of management systems
• ISO/IEC 17065:2012 — Conformity assessment: Requirements for bodies certifying products, processes, and services
• ISO/IEC 17024:2012 — Conformity assessment: General requirements for bodies operating certification of persons
• ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories
• ANSI National Accreditation Board (ANAB)
• American Association for Laboratory Accreditation (A2LA)
• NIST National Voluntary Laboratory Accreditation Program (NVLAP)