23 February 2026

REVEAL: Guidance on evidence-based planning of clinical trials

REVEAL provides researchers with a new, practical guidance on how to systematically identify and efficiently analyse existing evidence before planning a new clinical trial.

Many clinical trials continue to be planned without a systematic review of existing evidence. This can lead to unnecessary or methodologically poorly planned studies - with consequences for patient safety, resource consumption and scientific credibility.

In response this, the REVEAL guideline offers a structured, pragmatic approach that is specifically tailored to the needs of researchers especially those working with limited resources. The aim is to better justify research and facilitate the generation of new, relevant evidence.

Illustration using a practical example

Using the OSPIC study on oral corticosteroids in post-infectious cough, the team of authors demonstrates how REVEAL works in everyday research. The analysis of existing literature showed, among other things, that no previous trials had investigated the planned intervention - a clear indication of the relevance of the new study. At the same time, previous data supported the choice of the primary endpoint and the sample size planning.

The development of the guidance was conceived by the DKF research group of Matthias Briel at the CLEAR Methods Center of Clinical Epidemiology at the University Hospital Basel. It was funded by the Swiss National Science Foundation SNSF and implemented together with an international research team. REVEAL is intended to serve as a standard for evidence-based study planning in the future.

Conclusion

REVEAL offers clinical researchers a practicable tool for planning studies in a more informed way and improving research efficiency. The team of authors is planning further international usability tests - feedback from research practice is expressly welcome.