Friday is the final day of your sprint, when all your hard work pays off: the prototype you created on Thursday will be tested, preferably by a small sample of guest users.
For this phase, five is the magic number. Five guest users are all you need to get a good sense of your solution’s pros and cons. In fact, this optimal figure was first defined by Jakob Nielsen, a Danish pioneer in website usability.
Back in the 90s, Nielsen did a lot of individual testing on website designs and found that, in most cases, 85 percent of the design flaws were uncovered in the fifth interview.
So, five is the magic number and one-on-one interviews with guest users are the best way to observe their reactions. To lead one, the interviewer should start by welcoming the user in a friendly manner to put her at ease. Then, before presenting the prototype, the interviewer should ask the guest user some background questions to put her reactions into perspective.
For Fitstar, for example, it was relevant to know whether or not the person had prior experience with workout apps. After all, if the user was new to the world of fitness apps, she might struggle with Fitstar regardless of its good design.
But it’s also essential that these one-on-one meetings end with the guest user giving her opinion. So, simply ask her what she liked or didn’t, and what needs work.
And the rest of your team?
Well, while the interviews are taking place, they should be in another room watching the scene live. This way, they can write down their observations on sticky notes and post the positive and negative feedback on a whiteboard. This strategy will quickly let you know if your idea and prototype are up to snuff.