The COM-B System for Client Retention






A Review of behaviour change strategies (1) found that there may be as many as 93 items that would allow for active ingredients of behaviour change interventions to be systematically described. It is certainly beyond the scope of this article to investigate all of those but there are some useful lessons to be learnt within this review. The behaviour change wheel (2) is an attempt to synthesise this knowledge into a framework that can be applied across future evidence-based practice.

From a trainer’s perspective it is the COM-B system (2) (see header image) that is contained within the wheel that has a lot of potential. This is intended as a framework for understanding behaviour and it is a good place to start when considering an individual’s readiness to change.


Capability, when considering COM-B is the individual’s physical and psychological capacity to usefully engage in the desired activity. Your client’s capability is built from a number of strands. Being aware of these is important. Does your client have the required skills and knowledge, how have you assessed this? The processes that direct and energise direct behaviour are defined as motivation. Motivation sits in the middle being influenced by both capability and opportunity. Motivation theory is a key component of self-determination theory (SDT) (3). For the COM-B system motivation would incorporate a large number of concepts including:

  • Goals
  • Conscious decision making
  • Habitual processes
  • Emotional responding
  • Analytical decision-making

Opportunity sits on the opposite side of motivation from capability and is considered to be factors that are external to the client’s situation and that prompt a behaviour or make it seem possible.

In figure 1 you can see that the single headed arrows are highlighting the fact that both opportunity and capability can, and will, influence motivation. Whereas when you engage in a behaviour this will likely influence and/or alter the client’s capability, motivation and opportunity.

For the trainer the COM-B system offers a good starting point from which to assess their client’s readiness to change. By using proper engagement skills with the client (motivational Interviewing) they should be able to evaluate their client’s degree of capabilities around the change. They can also assess where opportunities exist to aid the change and the client’s degree of motivation (is this external or internal motivation – SDT). The trainer can get a feel for how successful the client is going to be. This assessment will be enhanced if the trainer has psychometrically tested their client’s readiness as well.

If this assessment highlights that a client lacks any of the three components of COM-B, then this presents a logical area to address from the start. For some trainers/coaches it might be tempting to think that it is all about education. This is assuming (not based on any data) that the client doesn’t know what to do. By undertaking an assessment of the three elements it might highlight that the client has a high level of capability, but their opportunities are lacking. Therefore, ploughing on with an education programme would be fruitless in terms of achieving a positive outcome.

Trainers need to consider psychological assessment in a lot more detail in the future. Jumping straight in with the same system or programme that you use for all clients is a perfect recipe for failure in the long-term. The assessment should be on-going, and programmes should be adjusted according to what the data is highlighting. Client results will improve, as will client retention. This can only be good for business.

  1. Meghan, R.N., Mitchell, N. and Backhouse, S. (2020). Sports nutrition interventions: A systematic review of behavioural strategies used to promote dietary behaviour change in athletes. Appetite. 150. 104645. 10.1016/j.appet.2020.104645.
  2. Michie, S., van Stralen, M.M. & West, R. (2011) The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Implementation Science. 6, 42.
  3. Ryan, R.M. and Deci, E.L. (2017) Self-determination Theory. The Guilford Press, London