The staircase of evidence – a new metaphor displaying the core principles of Evidence-based Veterinary Medicine

Abstract

Background: Veterinary practitioners and clinicians should base their clinical decisions on the best evidence obtainable to provide best patient care. The evidence of information concerning diagnostic or therapeutic procedures and disease prevention can be ranked from weak to strong based on the methodology the information is generated by. Teaching the concepts and strategies of Evidence-based Veterinary Medicine, however, can be challenging. Students and practitioners should become competent in defining a clinical problem, retrieving of information from the literature and independent critical thinking. Several authors illustrated the levels of evidence ranked from strongest to weakest using a pyramid metaphor. The basis reflects information of the lowest evidence and towards the tip the evidence increases. The metaphorical concept of the pyramid, i.e. solid foundation and a narrow tip, however, does not adequately represent the hierarchy of evidence as the high evidence levels are represented by narrow fields and vice versa. Results: We propose an alternative schematic which may be used in order to display the respective evidence levels as a staircase. A reading pictogram character illustrates that the search for information should start at the highest step. To assess which metaphor can be more easily interpreted and is intuitively accessible a survey among 5th semester veterinary students was performed which was completed by 100 respondents. According to the results both metaphors adequately display the hierarchy of evidence. The staircase better represents the fact that high evidence information is more likely to be true and that one should start to look for high evidence when searching information. In contrast more students found that the pyramid represents distracting information i. e. that opinions and information from the internet provide a solid knowledge base. Conclusions: The staircase of evidence displays better the evidentiary value of information and how to perform a search for information of high evidence compared to the pyramid of evidence. It therefore can help to teach information search and interpretation strategies in order to answer specific clinical questions.