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A cheat's guide to the COM-B behaviour change model

young woman on a bus

The COM-B model boils behaviour (B) down to three core components; capability (C), opportunity (O), and motivation (M).

In a nutshell

  1. Do people have the capability – the know how?
  2. Do people have the opportunity – the can do? 
  3. Do people have the motivation – the want to? 

This model for behaviour change is effective because it simplifies complex factors and recognises that to modify behaviour, we need to address at least one of these components. We describe it as the “know how, can do, want to” of behaviour change.

The model was developed by Professor Susan Michie, Professor at University College London, UK, where she is Director of the Centre for Behaviour Change. She and her team lead a systemic literature review of 19 different behaviour change models and synthesized the findings into the COM-B model. 

 Here is a cheat’s guide to using this behavioural change model.

Know how, can do, want to 

com-b behaviour change model

Let's look at an example of the COM-B model in action.

Looking at lapsed and infrequent public transport users, we evaluated how we could look at encouraging them to take advantage of a new bus service into the city, for their commute to work or other trips into the city such as going to the gym or other social events. 

The success of this would be measured by patronage of the new service increasing compared to the old service, as well as an increase in new public transport card registrations in the catchment area.

Here is how we applied the COM-B framework to this behaviour change challenge.  

Know How  

The first question to address is that of capability. This refers to whether we have the knowledge, skills and mental bandwidth required to carry out an action. 

Do people know how to do the behaviour physically? Do they have the right tools, equipment and physical capability? 

For example, when looking at bus usage, we considered whether lapsed users still knew how to top up their card and navigate the updated bus route. 

Do they know where the new bus stop is and the new route? These questions are all an important part of addressing capability. 

Can do  

The 'can do' is the opportunity factor, which refers to time, location and resources. Can people do the behaviour in their current environment and context? Can they do it with their current resources and available time? 

Social norms and cues also come into play. Can people do the behaviour in front of their social group, in their culture? Is it socially acceptable amongst their peers? 

When looking at public transport, for example, we considered whether people could catch the bus at a time that suited them, whether they could afford the new service, and whether catching the bus was something that felt socially acceptable to them.

Want to  

The 'want to' or motivation element relates to people's desires, impulses, and inhibitions. Do people want to do the behaviour, instinctually and in the moment? 

Public transport behaviour change for ‘want to’ raised questions such as are people motivated to catch the new service? Are we using the right motivators to help prompt them? 

Putting the know how, can do, want to of behaviour change into practice 

Here at TRA we have found it useful to analyse a number of behaviour change challenges through this model.  Whether it’s looking at how to get homeowners and investors to build more energy-efficient homes, looking at how to get elected officials to prioritize their own learning and development or understanding how to ensure Kiwis are keeping themselves safe and secure online.  

As always, it’s important to clearly define the behaviour change objective you’re trying to achieve. First define who the key audience is, define the behaviours you’re trying to encourage, factor in the context and conditions of those behaviours and outline your success measures.  

Then use the key know how, can do, want to prompts to help diagnose where the key barriers to acting are. These prompts can be used as a key checklist to understand both barriers and opportunities. The model also helps us zoom out beyond a particular lens or discipline, such as a marketing challenge, or CX or product problem to solve and tell the story that many factors are often required for behaviour change.  

Another example in action  

Behaviour change objective: Ensuring homeowners and builders are protected by contracts 

Audience: First-time homeowners completing a major renovation  

The behaviour: Putting a contract in place between the homeowner and the builder 

The conditions: Before building work commences  

Measured by: Number of contracts used for renovation work   

Know how:

  • Do new homeowners know that contracts are mandatory for building work over $30k? 
  • Do new homeowners know they can request a contract from their builder? 

Can do

  • Do homeowners have the mental bandwidth and time to ask for a contract? 
  • Do homeowners feel comfortable asking their builder for a contract or are they fearful this will cause their builder to choose another client? 

Want to

  • Are homeowners aware of the benefits of having a contract in place? 

Reach out to us today to hear more about how we can help you tackle big challenges with our understanding of human behaviour.

Lindsey Horne
Behavioural Insights Lead

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