What is linguistic validation?

Linguistic validation is providing a conceptually equivalent and culturally-sensitive adaptation of PRO Instruments intended for clinical trials, by following a special methodology. A major requirement is that the translation is straightforward and easy to understand as PRO Instruments are to be used during clinical trials involving patients of various backgrounds, including patients with a lower level of education. This is why it is very important that the linguistic validation undergoes the so-called cognitive debriefing step, i.e. practical interviews with target population patients officially diagnosed with the relevant pathology.

The Process


The linguistic validation process is not simple and you should allow approximately 2-3 months for a questionnaire to be fully validated using our standard methodology.


The first step is to actually consider which languages and countries the questionnaire needs to be linguistically validated for. This is very important because you often have the same language but different countries, e.g. you need your questionnaire to be translated into Spanish while the clinical trials will take place in Spain and Brazil. In this case the target population should be taken into consideration and the questionnaire has to be validated for both countries separately. The same is the case with English depending on whether the questionnaire has to be adapted for Canada, the USA, Australia, or the UK.


After ensuring the target languages and countries (i.e. locales), the instrument needs to undergo a review – the original instrument is analyzed for translatability and linguistic issues, such as appropriateness of the response choices for other countries, grammar, verb tense, and terminological inconsistencies, unclear instructions, confusing statements, and questions. If any issues have been found, they are communicated to the Developer of the questionnaire.

The next step in the linguistic validation process is called concept elaboration. During this phase, we define the concepts in each item of the questionnaire and submit the Concepts list, referred to as “Concepts Guide” to the Developer for further clarifications and approval.


Once the Concept Guide is approved, it is then sent, along with the original instrument, to two independent professional translators, native speakers of the target language. They produce two forward translations of the questionnaire without consulting each other. We discuss the results with the LPM (Local Project Manager) and create a reconciled target version of the questionnaire referred to as Target Version 1.


Using the blind back translation method, we send the reconciled forward version (target version 1) to an independent native-speaking professional back translator who translates the questionnaire back to the source language without having access to the original instrument. The translation of the target versions is necessary in order to perform a quality check and spot any discrepancies between the original questionnaire and the existing target version. We compare the back translation with the reconciled forward version while checking for any discrepancies. Based on this analysis we implement the relevant changes to the target language versions and produce target version 2.


The aim of this step of the linguistic validation process is to assess target version 2 for clarity, cultural relevance, and appropriateness by means of conducting face-to-face interviews with patients in the target country. We receive feedback on the questionnaire-related specific terminology and incorporate the clinician’s suggestions for changes if applicable. We select and interview at least 5 native-speaking individuals with a diverse background, e.g. age, education level, employment status. All of them are native speakers and reside in the target country.

Meanwhile, target version 2 of the questionnaire is sent to a clinician for review in order to ensure that the most relevant terminology has been employed.

The results from the cognitive debriefing step are summarized, evaluated and the suggested changes, along with the clinician feedback, are implemented in the questionnaire. Target version 3 is produced.


If the questionnaire is validated in more than one language, a comparison across all target versions is conducted in order to ensure that the translations are conceptually equivalent. If necessary, changes are suggested and discussed with each individual LPS. Target version 4 is produced.


The questionnaire undergoes two separate proofreading steps carried out by the LPS and by an independent third-party proofreader for any linguistic and formatting errors. Any necessary changes are implemented. At this stage, the target version is formatted and finalized.


The deliverables include:

  1. A project summary report that highlights the issues encountered and their respective solutions.
  2. Our certificate for providing a linguistically validated translation that is understandable, culturally relevant and conceptually equivalent to the original.
  3. Linguistically validated target versions of the questionnaire.

If you hesitate about what service to choose, please contact us to discuss your project specifications. Upon receipt, we will evaluate the project and will recommend you the most appropriate service. Alternatively, we will offer you a special service package tailored to meet your needs.

To receive a customized free quote now, use the contact form or send an email to office@viax-translations.com.

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