A Bayesian approach demonstrating that incorporation of practitioners’ clinical beliefs into research design is crucial for effective knowledge transfer

Abstract

New knowledge will only be used on farm if the underpinning research has an impact by changing the clinical beliefs held by veterinarians in practice. If practitioners currently hold very strong clinical beliefs, stronger future evidence will be required to alter those pre-existing beliefs and forge a new prevailing opinion amongst the veterinary community. This study aimed to investigate within a Bayesian framework, the beliefs of veterinarians regarding the efficacy of systemic antibiotics as an adjunct to intra-mammary dry cow therapy and the consequences for knowledge transfer. The beliefs of 24 veterinarians from five practices in England were quantified as probability density functions (‘prior beliefs’) using probabilistic elicitation. Classic multidimensional scaling revealed major variations in beliefs both within and between veterinary practices which included: confident optimism, confident pessimism and considerable uncertainty. Of the nine veterinarians interviewed holding further cattle qualifications, six shared a confidently pessimistic belief in the efficacy of systemic therapy and whilst two were more optimistic, they were also more uncertain. The prior beliefs were incorporated into Bayesian models that used a synthetic dataset from a randomized clinical trial (showing no benefit with systemic therapy) to predict how the veterinarians’ prior beliefs would alter as the size of the clinical trial increased. This study demonstrated the usefulness of probabilistic elicitation for evaluating practitioners’ beliefs. The major variation observed raises interest in the veterinary profession’s approach to prescribing essential medicines and has important implications for knowledge transfer; determining practitioners’ pre-existing beliefs is crucial as they fundamentally affect the strength of evidence necessary for knowledge to be transferred effectively from research into clinical practice. As in human medicine, an important reason why veterinary research has failed in the past to evoke change may concern the strength of the research produced relative to the strength of practitioners’ beliefs.