Why Behavioral Interventions Often Fail

Studies show that utilizing behavior change theories increases the likelihood of impact of behavioral interventions. Yet very few public health organizations leverage these powerful tools. Why is that?

One reason is simply that many of the available behavior change models are too complex or simply don’t provide clear enough guidance to be used by practitioners. But there are several easy-to-use and highly actionable behavior models that are increasingly being used, as Doug Evans has shown.

The model I have personally found to be most intuitive has only 3 constructs: motivation, ability, and prompt. The Fogg Behavior Model is an easy-to-use yet very powerful model. Fogg says that behavior happens when motivation, ability, and a prompt happen in the same moment.

The model can be nicely presented in a simple graph with motivation along the y-axis and ability along the x-axis. When both the motivation and the ability to perform a behavior are high, a person will adopt the behavior when prompted -- represented by the smiley face on the diagram below. When either ability or motivation is missing, a prompt will not work – represented by the sad face.

As you can see, Figure 1 provides a very simple explanation of contraceptive use among men in Pakistan. Simply put, it demonstrates that people with sufficient motivation and ability will adopt contraception when prompted. At the same time, people without sufficient motivation or sufficient ability will not adopt contraception, no matter how many times you prompt them.

Fogg talks about a threshold. If a person is above the threshold or action line for a particular behavior (i.e. they have sufficient motivation and sufficient ability), all they need is a prompt to adopt the behavior.

If a person is below the action line, they will either need more motivation or more ability to adopt a particular behavior. That’s where interventions come in.

Here’s a fun exercise to help you really understand the Fogg Behavior Model.

First, think about the behavior you have personally adopted. For instance, perhaps you have started exercising regularly in a gym or have decreased the amount of red meat you consume. Any behavior you have successfully adopted will work for this exercise. Then, do the following:

1. Think about your level of motivation to adopt the behavior. What was your level of motivation to exercise regularly? How much did you want to exercise regularly?

2. Think about the things that had to be in place for you to be able to adopt the behavior. Did you need to be part of a gym? Perhaps you needed a membership that you did not have. Were you able to increase your ability to exercise regularly by becoming a member of a gym? Were you able to carve out the time to dedicate to your new behavior (i.e. increase your ability to adopt the behavior)?

3. Think about the prompts that have played a role in helping you change behavior. A prompt could be as simple a reminder on your phone that makes a noise when it is time to take a break and go for a walk. A prompt can also be a note in your schedule to go to the gym at a certain time or a meeting with a friend to go for a run.

Now, try using it to analyze a behavior that you have not succeeded in adopting.

Let me know whether you found the model to be useful. What behaviors did you try to explain? In the coming weeks, I’ll provide more examples of how the model can be used and evidence of its effectiveness.