Test — let users break it
Put the prototype in front of real users and treat their confusion as data.
Key takeaways
- What it is: Put the prototype in front of real users and treat their confusion as data.
- Why it works: Testing closes the loop by replacing your prediction of how people will react with their actual behavior. Because you built cheaply, you can afford to be wrong and iterate. The mechanism is disconfirmation: you are actively hunting for where reality contradicts your model, not seeking applause.
- Evidence: Plausible mechanism, limited direct outcome data.
- Avoid: Fishing for validation — asking "do you like it?" and counting polite yeses as success, instead of watching where users actually get stuck.
Why it works
Testing closes the loop by replacing your prediction of how people will react with their actual behavior. Because you built cheaply, you can afford to be wrong and iterate. The mechanism is disconfirmation: you are actively hunting for where reality contradicts your model, not seeking applause.
How to do it
- 1Watch users use it without explaining or rescuing them; their struggle is the finding.
- 2Ask what they expected to happen at each step, not whether they "liked" it.
- 3Feed the surprises back into Define or Prototype — testing is a loop, not an ending.
What the evidence says
MechanisticMechanistic. Usability testing with a handful of users reliably surfaces most major problems; the broader principle of iterating on real feedback is well established across disciplines.
Honest caveat: The famous "5 users finds 85% of problems" figure is a usability heuristic, not a hard law; treat it as directional.
Common mistake
Fishing for validation — asking "do you like it?" and counting polite yeses as success, instead of watching where users actually get stuck.
IX Coach helps you design unbiased test questions and debrief the results honestly, so feedback drives the next iteration instead of your ego.
Practice this with IX Coach →