The practice known as “back translation” is defined as taking the translated text of a source document and translating it back into the original source language. For a translation from English to German, the German document would then be translated back into English and compared with the original source. Back translations are often requested when individuals are not familiar with the target language and they want to judge the quality of translations.

Back translation is part of the quality assurance process and can be used in various ways and with various degrees of rigor, depending on the objective. The most common objective is to identify actual or potential trouble spots in the translation as well as in the original text in order to remedy them. There are some situations where this practice is useful but there are also serious drawbacks.

When to use back translation?

It is mostly used for documents in which content integrity is so critical as to justify the extra time and expense of a second round of translation, followed by comparison and remediation. In such documents, which tend to be scientific or legal in nature, translation accuracy and readability have a bearing either on the validity or the outcome of a scientific study, or on legal or ethical liability.

Examples of such documents include

  • medical consent forms, especially for clinical trials
  • patient instruction material*
  • operations and training manuals
  • legal and financial reports
  • opinion surveys
  • election ballots

Documents with instructions or procedures may also benefit from this process. Back translation can point out places where something was misunderstood. But divergence between the source document and back translation may not necessarily point to a mistranslation.

Issues with back translation

When one or more parties are not aware of the fact that the translation is in fact a back translation, the translator may decipher the intent of the original translation and thus render a fully comprehensible back translation even if the translation from which he or she is working is unintelligible to native speakers of the target language.

In such situations, the translator will write an accurate, meaningful and understandable translation without pointing out the errors such as spelling and grammatical mistakes. In this case, it would be most useful to share specific instructions with the translator about the back translation process. For example, the translator can be instructed to document all spelling and grammar mistakes and mark the ambiguous areas.

Another risk may come up when instructions are given and the second translator is aware that it is a back translation but his/her competencies don’t match the level of experience and skills in the subject area. He or she may suggest deletions or additions leading to unnecessary exchanges with the original author and translator. It could create additional expenses and delay along with compromising the actual translation.

In light of the potential pitfalls of the back translation process, our recommendation is to use back translation with caution. Regulations and industry/corporate standards may require a back translation. In these scenarios, we will provide a back translation with adequate instructions and coordination of the linguists involved. However, there are situations where requesting an additional proofreading step instead of paying for a complete retranslation is more appropriate.

Like back translation, additional proofreading can be used to check the meaning and refine the translation. Assuming that the first stage of translation has already involved a translator and editor/proofreader in the target language, a second proofreader in the target language with the required subject-area expertise will successfully check for divergence in meaning and not just words.

Finally, make sure that the second proofreading step involves the source text. It is not enough to perform an in-country validation of the target text.

Back translation is not  a remedy for all translation ills, but when used correctly and in the appropriate circumstances, it can be part of an effective quality control process.

*Note added Jan 22 2014: For an example of when back translation may be required in medical translation , see the description of our project for Beekley Medical.

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