Translation Technology

Translation Quality Evaluation vs. Translation Quality Estimation

Learn the differences between quality estimation and evaluation and what roles they play in optimizing machine translation quality.

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June 30, 2023


In today’s interconnected world, website translation plays a crucial role in reaching global audiences and expanding businesses. However, ensuring the accuracy and effectiveness of translated content is paramount. Two important concepts that come into play in the realm of website translation are quality estimation and quality evaluation. Although they sound similar, they have distinct purposes and methodologies. It’s important to know the key differences between quality estimation and quality evaluation and their respective roles and significance in achieving high-quality website translations. 

Quality Evaluation 

Quality evaluation is a post-translation process that involves human assessment and feedback. It aims to provide a comprehensive evaluation of the translated content by considering linguistic, cultural, and functional aspects. Quality evaluation is typically carried out by professional human evaluators who are fluent in both the source and target languages and possess expertise in translation and localization. 

The evaluators analyze the translated content in terms of accuracy, fluency, cultural adaptation, consistency, and overall user experience. They also consider the specific requirements and objectives of the website, such as the target audience, industry standards, and brand guidelines. This human-centered approach allows for a nuanced evaluation, taking into account the intricacies of language and culture that automated algorithms may struggle to capture accurately. 

Quality evaluations uses machine translation (MT) evaluation metrics such as BLEU, NIST, METEOR, and TER. These metrics score machine translated segments by comparing them to a verified human reference translation. This ensures that the evaluation is easy to understand and work with, but it does make it so they are reliant on references which may not always be available. 

Quality Estimation 

Quality estimation, on the other hand, is a way of predicting what the quality outcome of a given translation will be. This task consists of estimating the quality of an output based on a certain input without yet knowing the output. Essentially, quality estimation is used to assess the machine translation model itself, not the actual quality of the output. 

The process involves machine learning techniques to evaluate the translation quality based on various linguistic and contextual factors. The primary goal of quality estimation is to provide a quick assessment of the translation quality to assist translators in making informed decisions and allocating resources effectively. 

The process of quality estimation typically involves analyzing factors such as fluency, grammaticality, adequacy, and overall understandability of the translated content. These factors are assessed by comparing the translated text against reference translations, existing bilingual resources, or linguistic models. By leveraging these comparisons, quality estimation algorithms generate scores or rankings to indicate the quality of the translation output. 

The results of quality estimation can be presented using standard data science metrics or in terms of the correlation of the predicted outcome and the decided standard. In terms of application, quality estimation is useful in the translation industry not only to evaluate the performance of machine translation, but it can also help you compare different translation algorithms based on a single metric. This can then help you decide which translations need to be set aside for human post-editing. 

Learn about machine translation and post-editing by downloading our FREE webinar recording here.

Key Differences: Quality Estimation vs. Quality Evaluation 

1. Methodology 

Quality estimation relies on automated algorithms and machine learning models to assess translation quality. It uses computational linguistics techniques and statistical analysis to measure various linguistic and contextual factors. In contrast, quality evaluation involves human evaluators who apply their linguistic and cultural expertise to evaluate translations based on predetermined criteria. 

2. Timing 

Quality estimation takes place before the translation process, providing immediate feedback to translators and enabling them to make adjustments and improve the quality of translations. Quality evaluation occurs after the translation process, allowing for a thorough assessment of the final product and providing insights for future improvements. 

3. Scope 

Quality estimation focuses on predicting the overall translation quality, offering a quick assessment that helps translators prioritize their efforts. It is a more automated and scalable approach that can handle large volumes of translations. Quality evaluation, on the other hand, examines the translation in a holistic manner, considering aspects such as cultural appropriateness, localization, and adherence to the specific requirements of the website. 

4. Subjectivity 

Quality estimation relies on objective criteria and computational analysis, minimizing subjective judgments. It provides a standardized evaluation based on predefined rules and linguistic models. Quality evaluation involves human judgment, which introduces subjectivity and allows for a more nuanced assessment, considering the target audience and specific context. 

Evaluation or Estimation: When Each is Appropriate 

Quality evaluation in translation should be utilized after the translation process to assess the final product and ensure its quality and effectiveness. Here are some key situations where quality evaluation is particularly beneficial: 

  • During a post-translation assessment of accuracy, fluency, and overall quality  
  • When evaluating the user experience aspects of the translated content to increase satisfaction 
  • To ensure the content complies with brand guidelines, values, and tone 
  • Reviewing aspects of localization like date and number formats, currency conversions, units of measurement, etc.  

Quality estimation has its own unique use cases: 

  • Hybrid translation, a workflow with both machine translation and human translations 
  • When estimating post-editing needs and efforts 
  • To validate final human translations 
  • When comparing machine translation systems or models 
  • For filtering training data for machine translations 

Prioritize Quality

In the realm of website translation, quality estimation and quality evaluation are essential processes for ensuring accurate and effective translations. While quality estimation offers a quick and automated assessment based on computational analysis, quality evaluation adds the valuable human touch, considering linguistic, cultural, and functional aspects. 

Both processes have their unique roles and significance in achieving high-quality website translations. Quality estimation aids in streamlining the translation process, assisting translators in allocating resources effectively, and making informed decisions. Quality evaluation, on the other hand, provides a comprehensive assessment that captures the nuances of language, culture, and user experience, ensuring translations meet the desired standards and objectives. 

Ultimately, a combination of both quality estimation and quality evaluation can optimize the website translation process, leading to accurate, culturally adapted, and user-friendly content that resonates with global audiences. By understanding the differences and leveraging the strengths of each approach, organizations can elevate the quality of their website translations and unlock new opportunities in the international market. 

Learn about the world of translation quality with our FREE webinar recording. Download here.

Last updated on June 30, 2023
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About Verity

Verity's avatar

Product Manager, Data Engineering


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