Why do we behave the way we do? How can we change behaviour?
The COM-B is a theoretical framework used in health psychology and behavioural science to understand the behaviour change process1. The framework is a part of the Behaviour Change Wheel1, which is a comprehensive tool used to identify the factors influencing behaviour change and to aid the development of effective interventions.
COM-B is an acronym for three key components that influence behaviour: Capability, Opportunity, and Motivation1. The framework proposes that for a behaviour to occur, an individual must have the necessary capability, opportunity, and motivation to perform the behaviour1. Our team was the first to apply COM-B to medication adherence,2 so I’ll use adherence as an example of how COM-B can be applied.
Capability refers to an individual’s physical and psychological ability to perform the behaviour1. Physical capability includes skills, knowledge, and physical strength required to perform the behaviour. Psychological capability refers to an individual’s mental capacity, such as executive function. In short, capability determines whether an individual can perform the behaviour.
Opportunity refers to the external factors that influence behaviour1. These factors include physical environment, social environment, and available resources1. For example, lacking access to healthcare or family discouragement are factors that might negatively influence medication adherence.
Motivation refers to all brain processes that drive behaviour, some of which the individual may be aware of, and some they may not1. Factors relating to motivation include emotions, habits, perceptions of illness and treatment, and confidence to perform the behaviour (self-efficacy). For example, medication non-adherence is likely when an individual isn’t convinced that medication is necessary or that it is working.
The COM-B model suggests that each of these three components (Capability, Opportunity, and Motivation) can either facilitate or hinder behaviour change1. Both Capability and Opportunity may influence Motivation, and performing the behaviour itself may influence all three.
For example, if administering your subcutaneous medicine is difficult due to physical incapacity (Capability) it may negatively affect your confidence to administer it (Motivation). As a person takes their medicine over time (Behaviour), their concerns about potential side effects may wane (Motivation). Lastly, the range of factors within Capability, Motivation and Opportunity may vary between individuals and within the same individual over time.
Advantages of the COM-B framework
The COM-B framework has several advantages over other behaviour change theories (e.g., the Health Belief Model, Theory of Planned Behaviour). First, it provides a comprehensive understanding of behaviour change by considering both internal and external factors that influence behaviour. Second, the framework can be used to develop interventions that target specific components, such as increasing an individual’s motivation or providing them with more opportunities to perform the behaviour. Third, the framework is flexible and can be adapted to various contexts and behaviours.
The COM-B framework has been applied across many areas of health and health conditions3,4,5,6. For example, Christina and Lina’s highly cited paper applying COM-B to the issue of medication adherence has influenced much adherence-related research over the past 10 years.2
In summary, the COM-B model is a useful theoretical framework for understanding the behaviour change process1. It provides a comprehensive understanding of behaviour change by considering internal and external factors that influence behaviour1, and can aid the identification of barriers and facilitators of behaviour in order to develop effective interventions1.
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Michie, S., Atkins, L., & West, R. (2014). The behaviour change wheel. A guide to designing interventions. 1st ed. Great Britain: Silverback Publishing, 1003, 1010.
Jackson, C., Eliasson, L., Barber, N., & Weinman, J. (2014). Applying COM-B to medication adherence: a suggested framework for research and interventions. European Health Psychologist, 16(1), 7-17.
Madhani, A., & Finlay, K. A. (2022). Using the COM-B model to characterize the barriers and facilitators of pre-exposure prophylaxis (PrEP) uptake in men who have sex with men. British journal of health psychology, 27(4), 1330–1353.
Silveira, S. L., Riemann-Lorenz, K., Heesen, C., & Motl, R. W. (2021). Current and Long-Term Physical Activity Among Adults with Multiple Sclerosis in the United States: COM-B Variables as Explanatory Factors. International journal of behavioral medicine, 28(5), 561–574.
Smits, S., McCutchan, G. et al. (2018). Development of a Behavior Change Intervention to Encourage Timely Cancer Symptom Presentation Among People Living in Deprived Communities Using the Behavior Change Wheel. Annals of behavioral medicine : a publication of the Society of Behavioral Medicine, 52(6), 474–488.
Mill, D., Seubert, L. et al. (2023). Understanding influences on the use of professional practice guidelines by pharmacists: a qualitative application of the COM-B model of behaviour. Research in Social and Administrative Pharmacy, 19(2), 272-285.