What Clause 5 Actually Governs
Clause 5 of ISO 17100:2015 is the operational heart of the standard. While earlier clauses deal with resources, competence, and pre-production agreements, Clause 5 is where the actual translation work happens. It defines a mandatory sequence of steps that every translation service provider (TSP) must follow for every project that falls within the scope of certification.
On this page
This is not a clause you can interpret loosely. The standard uses prescriptive language throughout, specifying who does what, in what order, and what must be documented. For TSPs seeking or maintaining ISO 17100 certification, Clause 5 is where most nonconformities are raised. For auditors assessing a TSP, it is where the audit trail either holds together or falls apart.
If you want to understand how the standard has been structured from the beginning, the earlier article on what ISO 17100 is and who it applies to provides useful background before working through the production requirements below.
The Four Core Production Steps
ISO 17100 Clause 5 establishes four sequential steps that must be performed on every translation project: translation, checking, revision, and verification. Two of these are mandatory in all cases. Two apply depending on the scope of the project agreement. Understanding which is which matters enormously for both compliance and audit purposes.
Step 1: Translation
The first step is translation itself. This sounds obvious, but the standard is specific about who may perform it. The translator must meet the competence requirements set out in Clause 3, which means holding a recognised qualification in translation, or demonstrating equivalent experience through a combination of education and practice.
The standard also requires that the translator work only into their language of habitual use. This is a firm requirement, not a guideline. A translator working from English into Arabic must have Arabic as their language of habitual use. TSPs that allow translation in the other direction without proper justification will find this raised as a nonconformity.
During the translation step, the translator is expected to use any applicable reference materials, terminology resources, style guides, or client-specific glossaries that were agreed during pre-production. These resources should have been identified and made available before work commenced, which connects directly to the Clause 4 pre-production requirements covered in the article on ISO 17100 Clause 4 pre-production agreements.
Step 2: Checking
After translation is complete, the standard requires a checking step. This is performed by the translator themselves before the work is passed on. Clause 5.3 specifies that the translator must check their own translation for completeness and correctness, including a review against the source text.
This step is sometimes underestimated in practice. Checking is not a casual read-through. The standard expects the translator to verify that all source content has been translated, that the target text is consistent with any applicable glossaries or style guides, and that there are no obvious errors in terminology, grammar, or formatting.
TSPs should have a documented process for this step. In an audit, you would expect to see either a checklist completed by the translator, a sign-off record, or a CAT tool workflow that captures the checking stage as a discrete event. If the only evidence of checking is the translator’s verbal assurance, that is unlikely to satisfy an auditor.
Step 3: Revision
Revision is the signature requirement of ISO 17100 and the one that most clearly distinguishes it from informal translation practices. Clause 5.4 requires that the translated text be revised by a second, qualified person who was not involved in the translation itself. This is a bilingual review, meaning the reviser must be able to work in both the source and target languages.
The reviser must also meet the competence requirements in Clause 3, which means they cannot simply be a fluent speaker of the target language. They must hold recognised translation qualifications or equivalent demonstrated competence. This rules out the common practice of having a bilingual subject matter expert review a translation without any formal translation background.
The revision step is where many TSPs struggle in practice. Finding a second qualified reviser for every project adds time and cost. Some smaller TSPs attempt to have the same person perform both translation and revision, or use a reviser who does not meet the Clause 3 competence threshold. Both approaches will generate nonconformities under an ISO 17100 audit.
The dedicated article on why revision by a second person is the signature requirement of ISO 17100 goes deeper into what auditors look for and how TSPs can build a compliant revision process.
Step 4: Review and Proofreading
Clause 5.5 and Clause 5.6 cover review and proofreading respectively. Unlike translation, checking, and revision, these two steps are not mandatory for every project. They apply when specified in the project agreement between the TSP and the client.
Review is a monolingual assessment of the target text against the agreed purpose and domain. It is typically performed by a subject matter expert rather than a translation professional. Proofreading is a final check of the formatted target document against the formatted source, looking for layout errors, missing text, and typographical issues.
The fact that these steps are optional does not mean they can be ignored when they have been agreed. If the project agreement specifies that a review will be performed, the TSP must perform it and document it. Failing to deliver an agreed step is a nonconformity regardless of whether that step is mandatory under the standard.
Exemplar Global Recognised Training ProviderRTP No. 310970
The Role of Tools and Technology in Clause 5
ISO 17100 does not prohibit the use of machine translation (MT) or computer-assisted translation (CAT) tools. However, it does impose conditions on their use. When machine translation output is used as a basis for a translation project, the standard requires that this be agreed in writing with the client as part of the pre-production process.
More importantly, using MT output does not remove the requirement for the full Clause 5 workflow. A translator who post-edits machine translation output must still perform the checking step. A second qualified reviser must still review the final text. The workflow does not compress simply because the initial draft was machine-generated.
In practice, auditors will look at how TSPs document their use of MT. If a TSP is using MT routinely but has not disclosed this to clients or has not adjusted their workflow documentation to reflect it, this creates a gap between the documented system and actual practice, which is one of the most common sources of nonconformities in any management system audit.
Documented Information Requirements Under Clause 5
ISO 17100 requires TSPs to retain documented information that demonstrates each step of the Clause 5 workflow was completed. The exact form this takes will depend on the TSP’s systems and tools, but the evidence must be sufficient to demonstrate conformity.
For an audit, you would typically expect to see:
- Project files or CAT tool records showing the translation was completed by a qualified translator
- Checking records or sign-off confirmations from the translator
- Revision records identifying the reviser, the date of revision, and ideally a record of changes made or a clean confirmation that no changes were required
- Review or proofreading records where these steps were included in the project agreement
- Project management records linking each step to the personnel who performed it
The project manager plays a central role in ensuring this documentation is complete. Their responsibilities under the standard include assigning qualified personnel, monitoring workflow progress, and ensuring that the full sequence of steps has been completed before the translation is delivered. The article on how the project manager role works in an ISO 17100 translation project explains this in more detail.
Common Nonconformities Raised Against Clause 5
Based on how ISO 17100 audits typically unfold, the following are the most frequently raised issues against Clause 5:
Revision Performed by the Same Person as Translation
This is the most common and most serious finding. The standard is unambiguous: revision must be performed by a second person. When a TSP cannot demonstrate that a different individual performed the revision, the finding is usually graded as a major nonconformity because it goes to the core of what the standard requires.
Reviser Does Not Meet Competence Requirements
Having a second person is not enough if that person does not meet the Clause 3 competence threshold. TSPs sometimes use bilingual administrative staff, subject matter experts, or native speakers as revisers without verifying their translation qualifications. This fails the standard even when the revision itself may have been thorough.
No Evidence That Checking Was Performed
The translator self-check is a required step, but it is often undocumented. If a TSP relies entirely on the translator’s word that checking was done, without any record to support this, an auditor has no objective evidence of conformity. This is typically raised as a minor nonconformity but is easy to fix with a simple sign-off process.
Agreed Steps Not Performed
When a project agreement specifies review or proofreading and the TSP cannot demonstrate these were completed, this is a direct nonconformity regardless of the optional nature of those steps under the standard. The agreement creates the obligation.
MT Use Not Disclosed or Documented
TSPs using machine translation without client agreement or without adjusting their workflow documentation are creating a gap between their documented system and actual practice. This tends to surface when auditors sample project files and find MT output in the translation memory or project history without any corresponding disclosure in the project agreement.
How Auditors Approach a Clause 5 Audit
When auditing Clause 5, the approach is straightforward: sample a selection of completed projects and trace each one through the required workflow. The auditor is looking for objective evidence that each mandatory step was completed, by a qualified person, in the correct sequence.
A typical audit approach would involve:
- Requesting a list of completed projects from the audit period
- Selecting a sample that covers different language pairs, project types, and project managers
- For each sampled project, requesting the project file and any associated records
- Verifying that the translator and reviser are different individuals
- Checking both against the competence records held under Clause 3
- Looking for checking records and any agreed review or proofreading documentation
- Reviewing how MT use is documented where applicable
The audit trail for Clause 5 is either complete or it is not. Unlike some management system clauses where auditors exercise more judgement about the spirit of a requirement, the sequential workflow in Clause 5 leaves little room for interpretation. Either a second qualified reviser reviewed the translation or they did not.
Exemplar Global Recognised Training ProviderRTP No. 310970Building a Clause 5 Compliant Workflow in Practice
For TSPs building or improving their compliance with Clause 5, the practical focus should be on three things: people, process, and records.
On people, the TSP needs a roster of qualified translators and revisers for each language pair they work in. This means maintaining competence records under Clause 3 and ensuring that the reviser pool is genuinely separate from the translator pool for each project. For small TSPs with limited staff, this may mean working with qualified freelancers, but those freelancers must still meet the Clause 3 competence requirements and their qualifications must be on file.
On process, the workflow needs to be defined in a way that makes the sequence of steps visible and trackable. CAT tools with built-in workflow stages are well suited to this. Project management systems that require sign-off at each stage before the next begins provide a natural audit trail. The key is that the process does not allow delivery until all required steps are recorded as complete.
On records, the TSP needs to retain enough documentation to demonstrate conformity for each project. This does not mean creating paperwork for its own sake. It means ensuring that the tools and systems in use generate a record of who did what and when, and that those records are retained in accordance with the documented information requirements of the standard.
Connecting Clause 5 to the Broader ISO 17100 System
Clause 5 does not operate in isolation. The quality of the production workflow depends directly on the pre-production work done under Clause 4, the competence of the people assigned under Clause 3, and the feedback and improvement processes that follow delivery under Clause 6. A TSP that gets Clause 5 right but has weak pre-production agreements will still struggle, because the project scope, agreed steps, and client requirements may not be clearly defined before work begins.
Similarly, a TSP that runs a technically compliant Clause 5 workflow but has no process for capturing client feedback or handling complaints will miss the continual improvement intent of the standard. ISO 17100 is a complete system, and Clause 5 is its operational core.
For auditors and quality professionals who want to build a deeper understanding of how translation quality management systems work, and how to audit them effectively, the ISO 17100 series of articles on Audit Workshop covers the standard clause by clause with practical audit guidance throughout.
