What is Guerrilla Testing?

I don’t know how many of you are familiar with “guerrilla testing”, but I’ve been doing it for a few years now and it’s a great way to get some quick user feedback on your product or idea.

To me, guerrilla testing means going into a coffeeshop or another public place to ask people there about your product or prototype. I typically rock up and check with staff that it’s ok to put a sign next to my laptop which will say something along the lines of “I’ll buy you a free coffee if you answer 2 questions about my app”. As simple and as obvious as this approach may sound, I’ve found it to be very effective whenever I’ve used it. You’d be surprised by the number of people who are happy to have a play with your app or prototype and give you valuable feedback.

A few weeks ago, I attended a presentation by Lily Dart, a London-based user design expert, who talked about Guerrilla testing for content. These are the main things that I took away from Lilly’s talk:

  1. Preparing a session  Lily started off by talking about how to best prepare a guerrilla testing session (see Fig. 1 below). If you have a target persona or user segment that you’re targeting, make sure you’ll be able to find them at your venue of choice. The other thing which I’ve learned – the hard way – is to always ensure that the staff at the public venue are happy with you doing some user testing.
  2. Start with a good intro – It was interesting to hear Lily talk about the importance of a well practised introduction (see Fig. 1 below). In reality, you’ll only have a few minutes to get across what you’re there to do and what you want from the participant, so you better get your intro right!
  3. Test scenarios – Like with regular usability testing, it’s good to have a few concrete scenarios or use cases to test with participants. Lily outlined the characteristics of what makes a good scenario: (1) easy for participants to relate to, (2) describes a problem for participants to solve, (3) a realistic level of detail and (4) doesn’t hint to the participant how to achieve the goal (see Fig. 1 below).
  4. Running a session – Even if you typically only have about 10 minutes for your guerrilla testing session, there are a lot of useful learnings that you can get out of running these sessions. Lily provided some useful pointers on how to run guerrilla sessions, highlighting some of the common questions/tasks to use during a session.

Main learning point: “A little bit of testing is better than none” was the phrase with which Lily Dart ended her talk. She’s so right about that one. Although your test results or learnings from guerrilla session aren’t statistically sold or representative, you’re still going to get useful feedback in a very cost-effective way. I therefore can’t recommend running guerrilla testing sessions strongly enough. Granted, it takes a bit of getting out of your comfort zone but the advantages of this approach are so worth it!

Fig. 1 – Practical tips from Lily Dart on how to best do guerrilla user testing sessions – Taken from:  Guerrilla testing for content

Preparing a session:


  • Where will you find your target audience?
  • Can they stop for 10 minutes?
  • Is it ok with venue staff to do some testing?
  • Will you have internet access?


  • Which devices does your audience use?
  • Can you record from that device?

Facilitating a session:

Practiced introduction

  • Who are you? (i.e. the facilitator)
  • Why are you there? (provide your user with context on your product)
  • What do you want from them (e.g. what are you looking to learn, explain the session)

Example of a practiced introduction

“My name is Marc and I work for a startup called “carwow”. I’m here asking people to have a quick look at my website and to share their first impressions. I’d like to record your answers which will help me massively in improving the site. In return, I’ll buy you a coffee or a muffin to say thank you.

Do you have 10 minutes to spare?”


  • Which user need are you testing?
  • What might create that need?
  • When has a user fulfilled that need?

Anatomy of a good scenario

  • A good scenario is easy for participants to relate to
  • A good scenario describes a problem for participants to solve
  • A good scenario has a realistic level of detail
  • A good scenario doesn’t hint to the participant how to achieve the goal

Running a session

  • Before a scenario – Ask participants to describe their thoughts
  • During a scenario – Let participants identify success
  • After a scenario – Let participants tell you what they’d do next

Fig. 2 – Image of a guerrilla usability testing session at a Starbucks coffee shop – Taken from: http://www.uxbooth.com/articles/the-art-of-guerrilla-usability-testing/

Guerilla testing

Related links for further learning:

  1. http://www.slideshare.net/LilyDart/guerrilla-testing-for-content
  2. http://www.uxbooth.com/articles/the-art-of-guerrilla-usability-testing/
  3. http://www.uxbooth.com/articles/guerrilla-research-tactics-tools/
  4. http://www.boxuk.com/blog/unboxing-guerrilla-usability-testing/
  5. http://www.quora.com/How-do-you-go-about-doing-user-testing-in-coffee-shops

One response to “What is Guerrilla Testing?”

  1. Hi Marc,

    A really interesting and simple approach for getting user feedback. I guess the challenge is, avoiding bias from your testers – though, as you said, a little testing is certainly better than none!

    I work for Testbirds, and we have a crowdtesting platform that allows for the collection of real user feedback on apps and websites, completely remotely – members of our crowd test your prototype/pre-launch/live product on their own device in their own home, on the tube, wherever. Maybe this would be an interesting way for carwow to get feedback too. We also have some cost effective options that match a startup’s limited resources.


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