Clinical practice guidance and education in ultrasound: evidence and experience are two sides of one coin!

In this issue of the Journal a new set of European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines is reported. Some years ago it was discussed how guidelines are prepared, but things are continuously changing. Initially, guidelines were mainly based on expert opinions due to the limited availability of high-quality evidence. Within recent years the paradigm that guidelines should be based on evidence has prevailed. However, if evidence was not available, recommendations continued to be based on expert opinions, which were not necessarily correct nor objective. The differences in the methodology of clinical guidelines are sometimes considerable, without this always being apparent to the reader at first glance. This concerns in particular the formulation of clinical key questions guiding the systematic retrieval of evidence, its evaluation, the process of transforming evidence into recommendations, and the rules for reaching agreement in the guideline panel on conflicting conclusions from the research evidence.