Why educational interventions are not always effective: a theory‐based process evaluation of a randomised controlled trial to improve non‐prescription medicine supply from community pharmacies

Objective The Theory of Planned Behaviour (TPB) has been used to explore health professionals' intentions to behave in a particular way. This study measured community pharmacists' behavioural intention and actual behaviour as part of an evaluation of a randomised controlled trial (RCT) of two educational interventions to promote the appropriate treatment of vaginal candidiasis in community pharmacies. This study aimed to explore reasons for the success or failure of educational interventions by conducting a theory‐based process evaluation alongside the RCT. Method The RCT was conducted in 60 community pharmacies in Grampian, Scotland, and compared educational outreach visits and continuing education workshops. A postal questionnaire was conducted, comprising five measures derived from TPB: behaviour; behavioural intention, attitudes, subjective norms, and perceived behavioural control; together with a measure of clinical knowledge of candidiasis and its treatment; and a measure of guideline compliance. Guideline compliance was assessed using four scenarios. Simulated patient visits were made to participating pharmacies to derive objective measures of actual behaviour. Results Completed questionnaires were returned from 50 pharmacists (response rate: 83%). Forty (80%) respondents were fully guideline compliant (correct response with all four scenarios). Pharmacists' knowledge was high and they had positive attitudes towards the supply of antifungals, as well as strong intentions to sell them appropriately. No statistically significant differences were shown in questionnaire responses or actual behaviour across the four trial groups. Conclusion This evaluation demonstrates that the interventions may have failed because of psychological ceiling effects, i.e. existing attitudes and intentions were already strong. Further studies are needed to identify factors that prevent strong intentions from being put into practice, in order to develop effective interventions.