An increasing number of writers have studied the work of Benner (1984) and Schon (1983) and have explored the concepts of expertise and ‘intuitive’ or ‘tacit’ knowledge. Efforts have been made to address the phenomenon of the theory–practice gap. Reborn interest in the craft of the professions is evident. A number of studies about the clinical decision-making process have suggested that clinicians are actually using a form of deductive reasoning known as hypothetico-abductivism whilst reflecting in action. Exploration of expert decision-making by psychiatric nurses requires first that the nature of psychiatric expertise be clearly described. However, literature shows that this is not an easy task. In order to facilitate the development of expertise in novice practitioners, further research is required into the nature of expertise and expert decision-making. Cultivating and recording reflection in action around expert decision-making has revealed greater insights into the gap between theory and practice. It is evident that there is a need for a model that makes sense of the informal theory that is generated through practice.