GLSP Language Toolbox


The process below is a recognised gold standard for language translation of information intended for study participants in clinical studies, for example Informed Consent Forms. It is also the recommended translation process in the Good Lay Summary Practice (GLSP) Handbook(1).

The process and scope of language translations for Lay Summaries is determined by the study Sponsor, and the Sponsor is recommended to plan translations already during the development of the Informed Consent Form.

Lay Summaries are written for the study participants and the general public. Since it is imperative that the summaries remain understandable and non-promotional after translation, the GLSP Handbook recommends the gold standard translation process as the ideal setup. The process involves different qualified and independent translators and a forward and back translation step. In case of Sponsor resource constraints, back translation and subsequent comparative review can be replaced by a linguistic review if the Sponsor deems it acceptable from a quality and risk perspective.

For more guidance, refer to the Good Lay Summary Practice (GLSP) Handbook at EudraLex, Volume 10, Clinical trials guidelines, Chapter V.

Translation Process Overview Diagram



Before language translation is initiated, the source text (master Lay Summary) should be analysed in order to identify potential areas of ambiguity, compliance or risk areas of promotional or biased language. This will facilitate decisions on glossaries, reviews or tools needed in the translation process.Source text analysis is typically performed by a linguist but may be performed by someone else who is trained in the Lay Summary process and understands lay Summaries/ clinical trials.



Forward translation is the process of translating a source text (master Lay Summary) into a target language (or languages, depending on the language scope determined by the Sponsor).Forward translation is performed by a qualified translator who is a native speaker or fluent in the target language and who has experience in the medical field/with clinical trials.



Back Translation is the process of translating a target text (the result of the forward translation) back into the original source language.
Back translation is a quality assurance step which is followed by a comparative review.
Back translation is performed by a qualified translator who is a native speaker or fluent in the source language and who has experience in the medical field/with clinical trials.
The back translator will not have access to the source text (master Lay Summary) but only to the translated Lay Summary.



Comparative review is the process of comparing the back translated Lay Summary with the source text (master Lay Summary).
Comparative review can help detect and resolve any discrepancies between the source text and the back translation with the intent to arrive at the best possible translation.
A third resource (not necessarily a translator) will perform the  comparative review.
The comparative reviewer will have access to the source text (master Lay Summary) and the back translated Lay Summary.





A final, thorough quality inspection is recommended if DTP (Desktop publishing) or other production quality steps have been included as part of the final file production.This step can be performed by an individual who is trained in the process.



The final output is the translated Lay Summary(ies) along with any translation certificates, as applicable.  This step can be performed by an individual who is trained in the process and who can verify that qualified translators were used in the translation process. 

Health Literacy Principles  Non-Promotional Language for Lay Summaries

A recommendation for the development of Lay Summaries is that they are written based on Health Literacy Principles in order to facilitate that the summaries are understandable for a general audience from the age of 12 years. These principles can in addition be a useful guidance for any subsequent language translations of Lay Summaries. Another good practice for Lay Summaries is that they are written in neutral, non-promotional language to avoid any unintended or biased interpretation of clinical study results. Core elements of Health Literacy and Non-promotional language are extracted below from the Good Lay Summary Practice (GLSP) Handbook(1).

Use simple, everyday conversational language
Use not Utilise
Long term not Chronic
Use short words, sentences, and paragraphsTo increase readability, it is recommended to use:
  • Words of 1-2 syllables
  • Sentences of 8-10 words
  • Paragraphes of 3-5 sentences
Use active voice rather than passive voice
Active voice is easier to understand. It reduces the risk of misinterpretation and can make sentences shorter.
Example: "Researchers studies the effect of tamoxifen", rather than "The effect of tamoxifen was studies by researchers."
Do not use technical or scientific language
"Birth control", not "Contraception"
"High bood pressure", not "Hypertension"
Present medical terms in brackets
Present medical terms in brackets after the plain language version.
Example: "Some people had side effects of feeling sick (nausea)".
Do not use statistical termsDo not use terms such as number needed to treat, odds ration and confidence interval
Quantify terms
Quantify words such as low, higher, faster, more, many, and ensure content is evidence-based.
Example: "Most were non-smokers (44) or former smokers (11)."
Use words and terms consistency
Do not alternate between interchangeable synonyms which will be more demanding for the reader.
Example: study versus trial
Be respectful in your language
"People with cancer" rather than "cancer patients"
Do not use Latin expressions
Such as not e.g.,
That means not i.e.,
In the laboratory not in vitro
Keep an overal factual and objective style/ton
  • Present information accurately and in a non-misleading way
  • Highlight both the positive and the negative
  • Present only opinions that can be substantiated clearly from the results 
  • Stick to facts and avoid making inferences or assessments
  • Do not criticize or oppose competitors
Avoid commercial or marketig appearance
  • Avoid using glossy designs and Sponsor logos and stick to neutrl colors and plain designs
  • Avoid using brand colors and brand names, except if the brand name is necessary for finding information
  • Ensure that reproduction and references to sources, quotations, graphs, diagrams, illustrations, etc. are presented faithfully
  • Avoid stating the approval status of the study products since their status may differ across regulatory territories and can lead to promotional concerns
  • Refer to study products as in the Informed Consent Form, the protocol and on clinical trial disclosure sites (most often generic names)
Avoid superlative and enthusiastic words
  • Avoid using words or expressions that could cause the audience to determine that the content is promotional or favorable, for example the best, extraordinary, or the highest. Such words are typically adjectives that modify nouns or pronouns and describe a particular quality of the modified word.
  • Avoid making claims that cannot be substantiated, for example the results proved.
Quantify statements
  • Numbers presented should be quantified and specific For example: of people % given X had low blood sugar" rather than "Fewer people had too low blood sugar while on X."
Clarify that results are from a single study only
  • Include a statement to ephasize that results presented are from a single study in order that no conclusions on the products overall performance are drawn from the Lay Summary. For example: "The outcome of this study is from the results of this study only. Other studies may show something different."
  • Do not include results from other studies which would be out of scope of the Lay Summary
  • Include relevant contrary evidence or limitations
  • Reinforce that therapeutic changes should not be made based on results from a single study without consulting a healthcare professional
Use high level statement with caution
  • Avoid generic statements that may lead to misinterpretation or unsubstantiated perceptions about the product. For example: "The study medicine is safe."
  • If generic statement are included, specify the circumstances they are based on. For example: " of people (%) given X had low blood sugar."
Ensure that additional information is readily available
  • For transparency, include references to additional results frrom the study, for example on external clinical trial disclosure sites. "Results from this study can be found on the listed website."
  • Consider including a statement on where to find results from other studies, if applicable