Tips for Training Post-editors
We have entered a new age, and a new technology has come into play: Machine Translation (MT). It’s globally accepted that MT systems dramatically increase productivity but it’s a hard struggle to integrate this technology into your production process. Apart from handling the engine building and optimizing procedures, you have to transform your traditional workflow:
Quality management issues are excluded.
The traditional roles of the linguists (translators, editors, reviewers etc.) are reconstructed and converged to find a suitable place in this new, innovative workflow. The emerging role is called ‘post-edit’ and the linguists assigned to this role are called ‘post-editors’. You may want to recruit some willing linguists for this role, or persuade your staff to adopt a different point of view. But whatever the case may be, some training sessions are a must.
What are covered in training sessions?
1. Basic concepts of MT systems
Post-editors should have a notion of the dynamics of MT systems. It is important to focus on the system that is utilized (RBMT/SMT/Hybrid). For widely used SMT systems, it’s necessary for them to know:
- how the systems behave
- the functions of the Translation Model and Language Model*
- input (given set of data) and output (raw MT output) relationship
- what changes in different domains
* It’s not a must to give detailed information about that topics but touching on the issue will make a difference in determining the level of technical backgrounds of candidates. Some of the candidates may be included in testing team.
2. The characteristics of raw MT output
Post-editors should know the factors affecting MT output. On the other hand, the difference between working on fuzzy TM systems and with SMT systems has to be mentioned during a proper training session. Let’s try to figure out what to be given:
- MT process is not the ‘T’ of the TEP workflow and raw MT output is not the target text expected to be output of ‘T’ process.
- In the earlier stages of SMT engines, the output quality varies depending on the project’s dynamics and errors are not identical. As the system improves quality level becomes more even and consistent within the same domain.
- There may be some word or phrase gaps in the systems’ pattern mappings. (Detecting these gaps is one of the main responsibilities of testing team but a successful post-editor must be informed about the possible gaps.)
3. Quality issues
This topic has two aspects: defining required target (end product) quality, and evaluation and estimation of output quality. The first one gives you the final destination and the second one makes you know where you are.
Required quality level is defined according to the project requirements but it mostly depends on target audience and intended usage of the target text. It seems similar to the procedure in TEP workflow. However, it’s slightly different; engine improvement plan should also be considered while defining the target quality level. Basically, this parameter is classified into two groups: publishable and understandable quality.
Evaluation and estimation aspect is a little bit more complicated. The most challenging factor is standardizing measurement metrics. Besides, the tools and systems used to evaluate and estimate the quality level have some more complex features. If you successfully establish your quality system, then adversities become easier to cope with. It’s post-editors’duty to apprehend the dynamics of MT quality evaluation, and the distinction between MT and HT quality evaluation procedures. Thus, they are supposed to be aware of the expected error patterns. It will be more convenient to utilize the error categorization with your well-trained staff (QE staff and post-editors).
4. Post-editing Technique
The fourth and the last topic is the key to success. It covers appropriate method and principles, as well as the perspective post-editors usually acquire. Post-edit technique is formed using the materials prepared for the previous topics and the data obtained from the above mentioned procedures, and it is separately defined for almost every individual customized engines. The core rule for this topic is that post-edit technique, as a concept, is likely to be definitely differentiated from traditional edit and/or review technique(s). Post-editors are likely to be capable of:
- reading and analyzing the source text, raw MT output and categorized and/or annotated errors as a whole.
- making changes where necessary.
- considering the post-edited data as a part of data set to be used in engine improvement, and performing his/her work accordingly.
- applying the rules defined for the quality expectation levels.
As briefly described in topic #3, the distance between the measured output quality and required target quality may be seen as the post-edit distance. It roughly defines the post-editor’s tolerance and the extent to which he/she will perform his work. Other criterion allowing us to define the technique and the performance is the target quality group. If the target text is expected to be of publishable quality then it’s called full post-edit and otherwise light post-edit. Light & full post-edit techniques can be briefly defined as above but the distinction is not always so clear. Besides, under/over edit concepts are likely to be included to above mentioned issues. You may want to include some more details about these concepts in the post-editor training sessions; enriching the training materials with some examples would be a great idea!
Selçuk Özcan serves as MT/QA Lead at Dragoman Ltd. He is mainly responsible for optimizing and testing MT engines, defining quality requirements, creating quality assurance (QA) solutions, and training team members. He is involved with developing and implementing quality and post-edit strategies, which involves performing data (bilingual or monolingual) and workflow management, and integrating quality principles into MT+post-edit processes.