Classification systems in behavioural science: current systems and lessons from the natural, medical and social sciences

Background: Specifying individual behaviour change techniques (BCTs) is crucial for better development and evaluation of behaviour change interventions. Classification of BCTs will help this process and can be informed by classification systems in the natural, medical and social sciences. Method: A search of the classification literature in the natural, medical and social sciences produced a framework within which to consider a systematic search of classification systems of BCTs in the behaviour change literature. Results: Six distinct types of classification system from other scientific disciplines were identified: nomenclatures, ordered sets, hierarchical, matrices, faceted and social categorisations. Eight classification systems of BCTs were identified, none of which had a formal, hierarchical structure. Most were developed for specific behaviours, although one was general. Discussion: Developing a hierarchical structure, similar to those used in other scientific disciplines, would enable better communication and understanding of BCTs and inform the development and evaluation of interventions. Hierarchical structured classification systems contain many of the characteristics most desirable in a classification of BCTs.