DesignqualitativeBeginner

Testing: Guerrilla

Quick and economical version of usability testing, conducted in informal settings with users not necessarily from target audience.

What it is

Main objective

Obtain quick and informal feedback on prototypes or ideas in early stages.

Detailed description

Guerrilla Testing is an agile and economical technique that consists of conducting quick usability tests in informal environments, such as cafés or public spaces, with users who do not necessarily represent the target audience. It allows obtaining immediate feedback on prototypes or initial ideas.

When it fits

When quick validation is needed with limited budget and in very early phases.

•In sketch or initial idea phases
•When quick validation is needed

Use cases

Startups with limited budgetEarly prototype validationMobile appsConcept testing

Effort level

Low

Recommended number of users

5-10 users in public spaces

What you gain and what you give up

Advantages

Low cost: It is extremely cheap (close to $0), since it removes lab and formal recruitment expenses.
Speed: It can be done at any time, with minimal preparation ("almost no preparation at all"), allowing fast iteration.
Accessibility: It lets small teams or startups with no budget do user research.
Breaks the ego bubble: It forces designers and developers to face the reality that their work can have flaws, breaking the internal team's "bubble."

Disadvantages

No statistical validity: The results cannot be extrapolated to the whole target population. It is not a scientifically "correct" methodology in quantitative terms.
Sample bias: Participants (people at a coffee shop, neighbors, family) may not represent the product's real user. Still, for general usability problems this is usually acceptable under the premise that it is "better to test with someone than with no one."
Superficial: It is not suited to in-depth research on complex workflows or latent needs, which call for methods like contextual inquiry.
Equipment logistics: Recording gear or the prototype can fail in the field, and the uncontrolled environment (noise, distractions) can affect the test.

How it is applied

Metrics

•Task success rate (%)
•Average time to complete tasks
•Number of errors per task
•Severity of detected problems (Nielsen scale)
•SUS (System Usability Scale)

How results are presented

Qualitative report with findings, usage patterns, quotes, and recommendations. May include session recordings, interaction heat maps, and visual synthesis of detected problems.

Practical example

Test paper app prototype in university café, asking students about registration flow.

Keep going

Related Resources

Tool

Sample Calculator

Calculate how many participants you need for your research

Service

Need to run this study?

Our team designs, executes and analyzes this methodology for your project