Guerrilla testing

Q: When should you use guerrilla testing rather than a classic user test?

The guerrilla format has the advantage of being very easy to set up. For a smaller investment, you can gather a few pieces of feedback on the specific points you are wondering about. When resources or time are short, it remains an option worth considering.

Q: What are the limits of guerrilla testing?

With guerrilla testing, there is no depth. You have little time, which stops you from going into detail. You keep to a few fairly targeted questions.

Q: How many people should you test in guerrilla testing?

Ideally, as many as you manage to persuade to answer you. At Akiani, we work in half-days at one location, sometimes alone, sometimes in pairs. Managing to interview six to eight people for around twenty minutes each over a half-day is a good score!

UX method

Getting quick user feedback

Guerrilla testing, sometimes called intercept interviews, means approaching users on the spot to ask for their feedback on a given theme or concept. There's no upfront recruitment, but you can filter for the right profiles. You head into the field and only the people who agree are interviewed. The respondents' characteristics, useful for the project, are noted to make sure feedback diversity is properly accounted for. Finding the right spot in a high-traffic location (to maximise potential participants), the right posture (an open attitude, getting past your shyness) and ideally a small gift (some sweets, goodies, a free drink and so on) all support the recruitment. Although it's labelled a "method", a guerrilla test is really a lightweight format for running individual interviews or user tests. We reuse the usual structure and methodology and adapt them into a simplified version that needs less preparation. This approach fits a "simple" project, where budget and timeline optimisation is the key: no recruitment overhead, everything is handled on the fly.

What is guerrilla testing for?

getting feedback from people outside the project
involving real users at low cost
gathering spontaneous user feedback
validating or invalidating a hypothesis or an idea
informing the design work

When to run guerrilla tests?

exploring behaviours around a defined topic
testing one or two scenarios using a prototype
checking how well a mockup is understood
during an exploratory phase of a study

Before going out

Define a light protocol and prepare the gear needed to gather the data. Print the guide and/or observation grid and keep them in front of you to run the conversation. Be aware that you sometimes need to adapt your wording and/or the order of the questions and scenarios depending on the person you're approaching. Target the spot(s) where you're most likely to find potential users of the service. (It can be in the street, in a café, near a specific venue, and so on.) Plan for the right format for the venue (e.g. a tablet to show an interface in a constrained setting). If you plan to settle in a private space like a café, give them a heads-up beforehand.

In the field

Approach the user when they arrive at the spot if possible, with a simple, quick opening line. Tell them how much time you need and the topic of your study. If needed, ask the user whether they're okay being photographed and/or recorded.

For the analysis

Filter the results by accounting for contextual biases: a noisy environment, behavioural biases (irritation, wanting to wrap up quickly, distraction, and so on). Analyse the results to surface insights and any other indicator you were after. A guerilla test rarely produces a detailed deliverable; a debrief with the client or the design team usually fits better.

Since meeting users is left to chance, nothing guarantees the representativeness or relevance of the profiles interviewed for the study at hand, but that’s not the point. Also, this approach mostly fits the general public and isn’t recommended for gathering feedback from professional profiles.

Lastly, time is limited with each user; don’t expect to test several scenarios on a prototype or dig deep into a specific topic.

When should you use guerrilla testing rather than a classic user test?

What are the limits of guerrilla testing?

How many people should you test in guerrilla testing?

Related methods

User testing

User testing means having target users assess the usability of your product or service. Depending on the goals, several approaches are possible.

Research protocol

The research protocol describes the conditions, the resources and how an experiment or test runs, along with the questions it sets out to answer.

Field observation

Field observation watches users in their real context, with a structured observation grid.

Prototype

More or less advanced animation of the screens to present a dynamic journey to users and gather feedback.

Usability

Usability measures whether a product lets its users reach their goals with effectiveness, efficiency and satisfaction, as defined by the ISO 9241-11 standard. An essential component of UX.

Sketching

Sketching is a technique for creating interfaces as drawings, most often by hand. It is often used in co-design workshops.

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