Creating clinical trial documentation in multiple languages can be challenging. To ensure compliance with regulations, the translation of clinical documents such as Informed Consent Forms (ICFs) and Clinical Outcome Assessment (COA) measures needs to be conceptually equivalent to the original text and culturally adequate for the intended audience. Back translation in clinical trials is a robust linguistic validation tool that helps producing reviewed translations which communicate the exact same meaning as the original text, are free of semantic errors and have relevance to the target audience.

To start with, what is a back translation?

In simple words, a “back translation” is the translation of an already translated text back into the language of the original text, made without reference to the original text.

Because it focuses on the accuracy of the “forward” translation (the transfer of a written text from one (source) language to another (target) language) and “cares” less about the style, the back translation is a literal translation. Comparing it to the original text, one can verify whether the content of the original text has been fully implemented in the forward translation and if the intended meaning is clearly and accurately conveyed. Any errors, serious discrepancies and ambiguities in the forward translation are pointed out and addressed.

In terms of required qualifications, the back translator must be a native speaker of the source language and have an excellent command of the target language, while the knowledge of the target culture and subject matter is highly desirable as well.

The back translation review is usually overseen by a Project Manager with strong linguistic skills. It results to a revised forward translation and a back translation of the new forward translation. This “reconciliation” process is documented in a discrepancy report, showing what has been changed and why. The aim is to decide on an optimum final wording that correctly conveys the meaning of the original document.

Why would you request a back translation service?

Clients, such as pharmaceutical companies, medical device companies or Contract Research Organizations (CROs), and Language Service Providers (LSPs) use back translation as an additional risk management step for complex and highly sensitive documents (clinical and pharmaceutical protocols, medical reports, ICFs and patient questionnaires), where translation accuracy is key, and errors have major impact.

Additionally, some local regulatory bodies, such as medical ethical committees (ECs) or institutional review boards (IRBs), recommend the submission of foreign language documents along with their back translation, as an evidence that translations have undergone an independent proofing process.

In the clinical trial industry, ethical and legal considerations apply. The US regulations state that the information presented in the ICF, including, among other things, the risks and benefits from the participation to the clinical study, along with the patients’ rights and responsibilities, must be given in a proper language that is clearly understood by the subjects enrolled in a study (or by their legally authorized representatives). Otherwise, their consent will not be educated, and may not be legally effective.

Furthermore, the increasing shift from the site-centric clinical trial model to the globalized model of multicenter clinical trials, including diverse populations (from clinicians and site personnel to patients) speaking different languages, demands for culturally relevant and scientifically accurate translations. It therefore imposes the need for an effective linguistic validation process that can ensure the consistent and precise communication of information and interpretation of data collected in multicultural settings, across shareholders. The rigorous quality requirements applying to this process are easily understood given that critical decisions (e.g., treatment options) depend on the validity of data pooled through COA instruments usually developed in one language and then translated for global use, in different countries and languages.

The benefits of back translation in clinical trials

Here’s why back translation works for translated material to be used in clinical trials:

  • It is a “blinded”, completely objective process. By revealing the slightest inaccuracies, misinterpretations of the information being communicated or shifts of meaning, back translation eventually “obliges” the forward translator to balance between the inevitably subjective understanding of the original text and the constraints of the context and target audience.
  • It flags errors and identifies problems in the forward translation. When the back translation matches the original text, one can be sure that the translation is accurate and correct, that there are no additions or omissions, no misleading or inappropriate words or expressions, renderings or terms that are medically incorrect or do not make sense and that complex nuances of the original text are retained in the translation.
  • It can reveal comprehension issues stemming from the complex and highly technical language of the original text, which can then be rectified by the authors, if needed, to avoid unwanted confusion.
  • It helps lifting the language barrier in contexts where accurately and clearly conveying the meaning, while considering the regional variations and cultural differences, is of critical importance. In the realm of clinical trials, the stakes are multiple: from communication and regulatory compliance to the patients’ wellbeing and defense in litigation cases involving subject injury.
  • It contributes to the avoidance of procedural and therapeutic misconceptions. Besides the legal, ethical and compliance risks it entails, the poor understanding of translated documentation can discourage people from enrolling to clinical trials, due to fear of the procedures involved, or otherwise adversely affect their capacity to make an autonomous decision about a medical treatment, which could, again, compromise the conduct of a trial.
  • It diminishes the danger of false assumptions regarding the attitude of the study personnel towards the participants: through back translation the desired tone and suitable register of the forward translation can be secured.
  • It is a means of identifying qualified translators for the specific type of documentation being translated, given that the Project Managers and the Quality Assurance personnel of the LSPs don’t speak all the languages that the company handles.
  • It helps improving the future performance of the translators through the feedback they receive for their work.

Are there any disadvantages in the back translation process?

The most obvious disadvantages are cost and time:

  • By almost doubling the volume of the text to be translated, back translation increases the cost of translation by about 80%. It also increases the lead time since it can only start after the forward translation is completed and it involves making the necessary comparisons and correcting errors. In this context, it is worth mentioning that patient-facing documentation, which is the most common type undergoing back translation, usually comes in short length and simple file format.


  • Considering what is an actual translation error and how things can be expressed into different languages can be a real challenge, at the comparison stage, while equivalent terms may not exist in the source and target languages.
  • The pool of qualified translators, who are competent in the medical field that the back translation concerns, varies and can be limited, depending on the language pair, which could also impact the budget and turnaround.


Taking into account the enormous waste of money and time, the possible damage to brand image and reputation, not to mention the direct and potentially harmful effects on human life, that can result from the misconduct of a clinical trial due to inaccurate translations, it would still be prudent to consider including back translation in clinical trials as an additional quality assurance step to the workflow, in order to eliminate language misinterpretations and vagueness in nuance.

Despite its limitations, back translation acts as a “window” to the forward translation, verifying the faithfulness of the translation to the original text. It guarantees that the translated content preserves the original meaning and intention, that it is equally reliable, valid, and effective as the original content, and that safety standards, as far as the linguistic part is concerned, are met. By doing so, it offers a return on investment and contributes to the successful implementation of multinational clinical trials.

If you want to learn more about our back translation services, visit our Life Sciences localization page.