Unit 4 · Lesson 13 of 20
State a testable design hypothesis
Name the person, task, change, expected effect, and possible failure.
01 / Learn
The idea
A design hypothesis makes a proposed change accountable. State whom it should help, in which task, why, and what evidence would count against it. 'A clearer response will improve UX' is too vague. 'Naming the affected zone aloud will help people who are away from the display notice a wrong-zone action before they leave the room' can be observed and challenged.
Include a competing risk. A longer spoken response may improve awareness yet become tiresome for routine commands. Define what to observe for both effects: whether people can say which zone changed, whether they correct an error, and whether they interrupt or disable the feedback. A hypothesis guides learning; it is not a prediction that must be defended after evidence disagrees.
A hypothesis is the same as a feature wish. A useful hypothesis states a mechanism and conditions under which it might fail.
02 / See the reasoning
Worked example
Fictional scenario
A home voice assistant sometimes turns off heating in the wrong zone after 'turn off the heat.'
An expert writes: 'When people issue an ambiguous heating command without viewing the display, a spoken zone name plus a short correction phrase will increase detection and correction of wrong-zone actions. It may slow frequent commands.' They prepare two task conditions and observe comprehension and friction rather than asking only which voice sounds nicer.
Try a decision →03 / Decide
Guided decision
Which first hypothesis would best balance error detection and routine friction in a useful test?
Feedback on your choice
What could change the answer: If wrong-zone actions are extremely rare but extra speech disrupts every command, a different intervention at the ambiguity point may be preferable.
This feedback helps you examine the decision; it does not grade your written reasoning.
Apply it somewhere new →04 / Apply elsewhere
Independent application
Fictional scenario
A web form proposes an inline summary of corrections before submission.
Write a hypothesis about error detection and a possible cost, then specify an observation that would challenge each part.
Make: A hypothesis and evidence table with task, expected effect, competing risk, and disconfirming observation.
The hypothesis is falsifiable, tied to a user task, and includes both intended benefit and plausible harm.
Lesson complete
You applied the method in a new context.
You studied the idea, tested a decision, and made an artifact for a new context. Keep the reasoning for your next UX question.
05 / Keep working