Guerrilla testing in Product Design

A fun, cost-effective, and insightful approach to product testing

As a digital designer, an important part of my role involves conducting user testing — a process where we observe people using our service to learn how they interact with it. This is integral to continuosly refine and improve our digital solutions. In order to do this we often rely on professional user recruitment agencies which is a convenient and effective way of getting user feedback. While convenient, this method can sometimes skew our insights for the following reasons:

  • To be a tester you are more tech savvy than the average person
  • The participants are pre-selected individuals already familiar with the user testing format
  • They are paid to participate and want to leave a good impression
  • In real life people they arein a completely different context and might for example be in a rush

To bridge this insight gap, guerrilla testing could be a good alternative or a supplement to the insights gathering. Guerillia testing involves going out into public spaces and inviting random individuals to test the solution. The spontaneous nature of this method garners more unfiltered and genuine reactions because they most likely are less patient and don’t get paid a significant amount of money. In the following sections, I will share practical strategies and guidelines for effectively implementing guerrilla testing into your work – ensuring you capture the most honest and constructive feedback.

Goal for the testing

Do you have a specific goal for the testing? Make sure that you have discussed this with your teammates before planning. However, be careful not to get too rigid with the goals and let it discourage you from going out in the first place. Whatever you do, going out there engaging and talking with random people about your product is better than not doing it. Try to formulate a sentence about what you want to get out of the testing. This could be a hypothesis, question, or general feedback on part of a service.

Make a basket of goodies

You need to give people something as a thank you for their time. However, there is a balance of how much or how little you should give people. If the prices are too good, you risk people becoming overly friendly and positive, and if your prices are too cheap and uninteresting you might not get anyone to test on. I have found a good balance in a basket filled with fruit, protein bars, chocolate bars, bags of nuts etc. Make sure you have healthy options, not so healthy options and alternatives for people with allergies.

This image is created using DALL-E, an AI image generation model developed by OpenAI

Prep your prototypes and questions

Make sure to prepare your prototype and test it with a few colleagues to make sure all the buttons and interactions work as intended. Also, prep some warm up questions you could ask that would give you valuable insights into their background. However, do not make a script with tons of questions, just start with an open question and see where the conversation takes you. It's easy to lead participants to certain answers, especially when you're passionate about the product. Try to remain neutral and open-minded to receive honest feedback.

Finding an optimal place

It is crucial to find a place where people have time to talk to you. Some good places could be:

  • Train stations in the waiting area
  • Cafe’s (make sure to ask the employees before approaching the guests)
  • Public parks
  • University Campuses
  • The beach or places where people chill
This image is created using DALL-E, an AI image generation model developed by OpenAI

Opening lines

Having a good initial line to make sure you don’t scare people away. Your opening line should convey the following:

  • Who you are and what company you’re coming from
  • You are NOT selling them anything
  • What you want from them
  • How much time you need from them
  • Say what they will get as a thank you
  • Make sure you bring your company badge to increase trust

Be prepared for rejection

You need to be prepared that a lot of people might not want to or have time to talk to you and that is completely fine. Do not take it personal or let it affect you negatively. Continue approaching people with the same positive attitude as before.


Phones are very unhygienic and especially phones for testing. This might turn people off if they don’t feel like it is clean. Therefore, bring hand sanitisers and cleaning napkins for the devices and do the cleaning in front of them.


In the beginning I was very optimistic on how many people I would be able to talk to, however I realised quickly it takes more time and energy than I expected. The latest guerrilla testing I have done I have been able to do 6 tests within 1,5 hour, after these I was really drained and tired. I would also recommend doing it in the morning before lunch when your mind is the most connected.

Some final tips:

  • Don’t do it alone. Bring a colleague with you for moral support and to help you document the findings.
  • Always inform participants about how their insights will be used.
  • Do a quick debrief with your colleague and write down your main takeaways after each test. You forget very quickly and this will save you a lot of time inn the work afterwards.

In summary, guerrilla testing is an affordable, and insightful method for gathering authentic user feedback – complementing other user testing approaches. I hope these tips could help you implement this into your own workflow as well.

More similar articles

December 7, 2023

How to facilitate online meetings

In this article I explore effective strategies for facilitating engaging and productive online sessions, offering tips for enhancing communication and participation.
Read full article
January 4, 2024

A Guide to Personal Diary Writing

Explore the power of journalling to improve your performance, focus and well-being.
Read full article