Behavioural diagnoses are about understanding the influences on why your target behaviour is, or is not, occurring. The COM-B model is the preeminent model to understand behaviours [2]. Traditional, and often implicit, logic models of behaviour might suggest that if you simply add enough awareness of a problem or behaviour, then you’ll see a corresponding behaviour change. This is what we see at the centre of many ‘hearts and minds’ approaches to behaviour change. 

However, as anyone who has ever tried to eat better, or exercise more, or develop healthier habits knows, awareness isn’t enough to change behaviour a lot of the time. The COM-B model is a leading, comprehensive, and scientific model of behaviour. It describes how for a behaviour (B) to occur, the person must have the capability (C), opportunity (O) and motivation (M). By understanding which of these COM-B components is lacking, we can more precisely design effective behaviour change interventions. Behavioural diagnoses help us understand what needs to change.

 How to conduct behavioural diagnoses

A behavioural diagnosis can start with a literature review, or with quantitative or qualitative research. A literature review involves reading academic research relevant to your target behaviour to understand what might be influencing whether the behaviour happens or not. Quantitative research might involve surveys and questionnaires with the targets of behaviour change (or other experts) to understand their perspectives. Qualitative research might involve focus group discussions, interviews, or observational studies to understand the target behaviour.

At this stage, it is critically important to ensure that your behavioural diagnosis is focused on your target behaviour. In the example we have been working through, this means that we want to understand what influences whether procurement/purchasing managers refrain from last-minute change to orders (without adequate adjustments).

This means that we want to stay laser focused on this behaviour. We do not want to get distracted by research on adjacent issues. Sometimes there will not be literature on your precise target behaviour. In this case you may be able to find related literature to draw inferences and collect your own data if possible. For example, I conducted a behavioural diagnosis to understand the influences on workers submitting grievances using worker voice apps. There was no literature on this specific behaviour, but I was able to draw on insights more broadly from research into the psychology of whistleblowing, the uptake of digital technologies, and psychological safety as a precursor to speak-up behaviours. In an ideal world, I’d also collect my own quantitative and/or qualitative data, but this wasn’t possible in this instance.

Next, you can categorise your findings using the COM-B model. You can think about what might be influencing your target behaviour in terms of somebody’s capability, opportunity, and motivation to perform the behaviour. This is important because when you design your interventions, you can ensure they precisely pinpoint those underlying influences on behaviour.

Next, you can translate those influences on behaviour into what needs to happen for the target behaviour to occur, noting whether it is important to change it. Below I’ve provided an example of how this might look in our procurement managers example.

Through this process, we are beginning to pinpoint where our intervention might land. We are being laser focused on what is going to lead to meaningful change and what will ultimately contribute to our larger goal. This concludes my overview of stage one of the behaviour change process.

Later stages of the BCW provide guidance on how to design your intervention through identifying intervention, content and implementation options, and how to implement and evaluate your behaviour change process. Research suggests that interventions designed using the Behaviour Change Wheel are more effective in achieving behaviour change than those following no such process [3]. You can read more about how to design interventions in the Behaviour Change Wheel [4] book, and you can download and browse the Behaviour Change Technique Taxonomy [5] app. I hope this has been a useful introduction to behavioural diagnoses and how to understand influences on behaviour. Let me know your thoughts!

[1] Michie S, Atkins L, West R. (2014). The Behaviour Change Wheel: A Guide to Designing Interventions. London: Silverback Publishing.

[2] Keyworth, C., Epton, T., Goldthorpe, J., Calam, R. & Armitage, C. J. (2020): Acceptability, reliability, and validity of a brief measure of capabilities, opportunities, and motivations ("COM-B"). British Journal of Health Psychology, 25(3), 474– 501.

[3] Kolodko, J. & Schmidtke, K. & Read, D. & Vlaev, I. (2021). #LetsUnlitterUK: A demonstration and evaluation of the Behavior Change Wheel methodology. PLOS ONE. 16. e0259747. 10.1371/journal.pone.0259747.

[4] Michie S, Atkins L, & West R. (2014). The Behaviour Change Wheel: A Guide to Designing Interventions. London: Silverback Publishing.

[5] Michie, S., Richardson, M., Johnston, M., Abraham, C., Francis, J., Hardeman, W., Eccles, M. P., Cane, J., & Wood, C. E. (2013). The Behavior Change Technique Taxonomy (v1) of 93 hierarchically-clustered techniques: building an international consensus for the reporting of behavior change interventions. Annals of Behavioral Medicine, 46(1), 81-95.