Research Methods: Critical Incident Technique

Michael Brown

The first in this series of blogs exploring design research methods focusing on one of my go-to approaches for interviews and surveys alike: Critical Incident Technique (CIT), also known as The Critical Incident Method. Originating in the 1950’s, this style of research really focuses on the idea that researchers should study behaviour and experience rather than opinion.

The underlying philosophy of the Critical Incident Technique is simple: get participants to talk about important or impactful events they have experienced first hand. So instead of asking what someone thinks of a website that they use regularly, ask them if they can remember a time that the website really helped them or conversely when it really got in the way of what they were trying to do. This focus on actual events lets you identify important problems and key advantages that have had a real world impact and avoid vague opinion based feedback.

How to do it:

This approach is great early in the process of redesigning or improving an existing product that has been in the market for a while. It can also be used with high fidelity prototypes in diary study type research but only with extended use of the prototype; if participants are only going to use prototypes for an hour or two direct observation is going to get you richer information.

The approach is relatively easy to apply during interviews as you can prompt participants to give more detail and guide them back to actual experiences if they get derailed. Building the Critical Incident Technique into a survey is trickier, as poorly phrased questions can mean you don’t get the detail you need to get actionable insights. So, the first time you use this approach I’d highly recommend running a few interviews first in order to get a feel for the type of questions that work in the context you are working.

Example Interview Script:

Thinking about your experiences using the product I want you to think about the last time it really helped you do your job and describe it in as much detail as possible.

Can you think of any other examples of the product really helping you? [try to elicit three positive examples from each participant]

Now I want you to think about times the product has got in your way or not helped you and again describe it in as much detail as possible.

Can you think of any other examples of the product really hindering you? [try to elicit three negative examples from each participant]


  • Why was that helpful/unhelpful?

  • What was it about the product that influenced that situation?

  • What were the consequences of that for you and your company?

Key Advantages:

  • Flexible: can be applied during interviews, in surveys and easily combined with other methods in one session.

  • Experience-based: focuses participants on the practical advantages and disadvantages of a service or product.

  • Identifies major issues: focusing on events that participants remember means that they are more likely to mention only major problems (and advantages) of the service/product.

  • Captures positive and negative: by asking about both positive and negative experiences CIT gives a well rounded view of the services/products being researched.

Key Constraints:

  • Dependent on memory: responses might be based on misremembered information.

  • Experience is needed: in order to have events to talk about participants must have significant experience actually using the product/service, so CIT isn’t appreciated for testing early prototypes or after limited use.

  • Doesn’t capture minor issues: smaller issues and those easily overcome are unlikely to be remembered or reported.

Find out more:

Read the original article by John Flanagan 

Detailed in ‘How To’ in the Usability Body of Knowledge


Finally, if there are any Research Methods in particular you'd be interested in, please just let us know and we may feature them in the up-coming series.