What is Guerrilla Usability Testing?
Guerrilla testing (also referred to as hallway usability testing) is a relatively quick and informal way to test ideas, get high-level feedback, and potentially uncover user experience problems. It aims to cut out the time-consuming parts of the user testing process and can be done anywhere; a coffee shop, a shopping center, or on the street.
Guerrilla testing works for the simple reason that testing it with people who haven't seen the design yet. It works best as a type of formative test, which means it is especially useful when you need to validate particular assumptions and identify major usability problems in the design process.
For example, if you need some quick data to test the initial direction of your design and user interface - but don't want to go for a usability testing process, then you can conduct Guerrilla Usability Testing.