ISO 18587:2017 Translation services — Post-editing of machine translation output — Requirements

Published on 22.01.2021

Industry Standards Demystified – Part 5

By: Monika Popiolek, ATA TCD Newsletter and Blog contributor and ISO/CEN industry standards expert

ISO 18587:2017 defines some best practices for managing post-editing of machine translation output and sets minimum requirements that have to be met in order to demonstrate translation service provider’s (TSP’s) conformity with the standard.

The reasoning behind the standard is that the use of machine translation (MT) systems has become very popular and hence the translation and localization industry has been experiencing and increased demand for MT post-editing services. Furthermore, it is argued that Translation Service Providers (TSPs) and clients have come to realize that the use of MT systems plus post-editing is a viable solution for translation projects that need to be completed within very tight time frames and/or with reduced budgets, uniform, very high volume or repetitive projects. Last but not least, some studies seem to indicate that thanks to the use of MT (with post-editing) a lot of content that would otherwise remain untranslated is made available to the public in multiple languages (and languages of small diffusion), overall translation costs can be decreased and the launch of products on specific markets, as well as the flow of information, can be accelerated and facilitated.

It is posited in the Introduction to the ISO 18587:2017 standard that TSPs implementing its requirements in their MT post-editing process will be able to:

  • a) improve translation productivity,
  • b) improve turn-around times,
  • c) remain competitive in an environment where clients show an increasing demand for using MT content.

The caveat here is that there are still no MT systems with an output which could be qualified as equal to the output of human translation, therefore the final quality of the MT output still depends on human translators and, for this purpose, their competence in post-editing. The rate at which MT systems are evolving nowadays makes it impractical to produce overarching ISO standards in this area, so ISO 18587:2017 therefore restricts its provisions to that part of the process which begins upon the delivery of the MT output and the beginning of the human process which is known as post-editing.

In general, ISO 18587:2017 provides requirements for the core processes, resources, and other aspects necessary for the delivery of an MT post-editing service that meets applicable specifications. Applicable specifications can include those of the client, of the TSP itself, and of any relevant industry best-practice.

The Scope of ISO 18587:2017 states that the document provides requirements for the process of full, human post-editing of machine translation output and post-editors’ competences and it is intended to be used by TSPs, their clients, and post-editors. It is only applicable to content processed by MT systems and ISO 17100:2015 is referenced here as the standard that deals with translation services in general.

ISO 18587:2017 defines a set of best practises for providing MT post-editing services and sets minimum requirements that have to be met in order to demonstrate translation service provider’s (TSP’s) conformity with the standard. In theory, adhering to these best practises and requirements helps design and manage a process that delivers post-edited content which meets the client’s specifications.

ISO published this standard in April 2017 as the first international standard for MT post-editing service requirements. While it is not considered to be the most well written or useful standard out there (because some of the requirements are obviously unrealistic and ignore actual industry practice) it is definitely a standard that industry players should be aware of. This version of the standard will probably undergo extensive revision in 2023.

There are several key requirements which the TSP must adhere to in order to meet the requirements of ISO 18587:2017. The TSP needs to assess the relative quality and its suitability for MT plus PE (in consultation with the client) prior to making an offer and recruit qualified and competent human resources as well as proper technical resources, and design a process which meets the requirements of the standard. ISO 18587:2017 also states that the TSP shall be fully responsible for the entire post-editing project.

Human resources are important to the standard. There must be a documented HR process in place (for recruiting qualified post-editors). The standard also sets out specific qualifications and competences for the various people involved in a translation project and the post-editor’s competences are very similar to the minimum requirements set for translators in ISO 17100:2015. However, it is not enough for the TSP to check that the human resources (mainly post-editors) have the required competences and qualifications but they must also be kept on record and updated regularly.

ISO 18587:2017 states that there must be a written agreement between the client and the TSP. If the client and the TSP come to this agreement over the phone or email, the TSP is expected to write it up and send it to the client as confirmation of what has been agreed. The agreement has to reference all the commercial terms and project specifications.

The standard additionally specifies that there must be a process to obtain feedback from post-editors on the performance of the MT system which can, when appropriate, provide input towards improvement of the MT systems used and processes followed. The TSP has to ensure that the post-editor always meets the following objectives during the post-editing process:

  • comprehensibility of the post-edited output,
  • correspondence of source language content and target language content,
  • compliance with the post-editing requirements and specifications defined by the TSP.

The TSP also has to ensure that the following requirements are met and issues taken into account when post-editing TM output:

a) terminological-lexical consistency and compliance with the domain terminology,

b) use of standard syntax, spelling, punctuation, diacritics, special symbols and abbreviations, and other orthographical conventions of the target language,

c) compliance with any applicable standards,

d) applicable formatting,

e) suitability for the target audience and the purpose of the target language content,

f) compliance with the client – TSP agreement.

Additionally, if applicable, the TSP shall ensure that the following requirements are met:

– compliance with client terminology or any other reference material provided,

– compliance with any proprietary and/or client style-guides,

– compliance with post editing guidelines.

The TSP shall ensure that the following tasks are performed by the post-editor:

  1. reading the MT output and evaluating whether reformulation of the target language content is necessary,
  2. using the source language content as reference in order to understand and, if necessary, correct the target language content,
  3. producing target language content either from existing elements in the MT output or providing new translation.

Under the final verification and delivery requirements, the TSP is obliged to have a process for these stages and for dealing with feedback.

In terms of post-editor competence and qualifications, the ISO 18587:2017 requires that the post-editor meets basically the same competences and qualifications as required by ISO 17100:2015 but additionally fulfil some ‘professionalism’ requirements which boil down to knowledge of MT technology, CAT tools and the applicable processes. So, these are in fact technical skills rather than professional requirements.

ISO 18587:2017 sets requirements for full post-editing and only mentions other levels of post editing (such as light post-editing). This, however, is not described in the standard but just referenced in informative Annex B. Moreover, the listed requirements for full post editing are actually a repetition of requirements already set in other sections of the standard.

In spite of the fact that the usefulness or relevance of ISO 18587:2017 in practice is highly debatable, there are several certification schemes in place (e.g. the Bureau Veritas Certification one) and some TSPs (but relatively few) have chosen to certify against this standard and thereby promote their post-editing services.


Author information: Monika Popiolek has an MA in English, an Executive MBA and is a graduate of a PhD Management Programme. She has been a specialist translator and interpreter for over thirty years and is also an authorised certified legal translator, CEO of MAart Agency Ltd. since 1991, President of the Polish Association of Translation Companies (PSBT) since 2009, Head of National Delegation and Chair of the ISO TC 37 Mirror Committee at PKN, OASIS, ISO and CEN expert since 2007, the EUATC Liaison Rep. to ISO TC 37, member of ATA, and many other organisations. Monika is the author of many publications, member of the editorial board of the JIAL journal (John Benjamins Publishing Company) and has presented at more than 25 international conferences. Her research specializations are: quality management, translation quality assurance, specialist translation and standards (particularly  ISO 17100, ISO 9001, ISO/IEC 82079-1, ISO 27001, ISO 20771). She was one of the editors for the ISO 17100 (Translation services – Requirements), Project Leader for two ISO standards (ISO 20771 and ISO 21999), and is the manager of the ISO TC 37 LinkedIn Industry Standards Group.

You can find and contact her on LinkedIn: