← Home
Design constraints
The rules this tool must hold to. Every UI decision should be checkable against these.
The framing rule
This is a research data-collection tool, not a game. The goal is to elicit honest expression from children with PDA, not to maximise engagement.
If a UX pattern would help a commercial product retain users, that is a strong reason to not use it here. Engagement loops, completion pressure, and reward mechanics are exactly the demand cues this population avoids.
The seven constraints
1No completion pressure
- No progress bars showing "how much is left"
- No "X of Y complete" counters
- No "almost done!" prompts
- No locked content that requires earning
- No streaks, points, or score totals
The participant should never feel that finishing is expected of them.
2Skipping is first-class
- Every prompt has a visible, easy "skip" option that is identical in prominence to the response options
- Skipping is a valid response and is captured as data, not as failure
- No copy implies the participant should answer ("you haven't answered yet", "are you sure you want to skip?")
3The Stop button is always visible
- A "Pause" or "Stop" affordance is present on every screen
- It is always at the same location
- It works on every screen without exception
- Pressing it does not produce a "are you sure?" dialog
4Predictability over novelty
- The Guide character is consistent in tone and presentation throughout
- UI element positions do not move between scenes
- Response mechanics for the same type of question are consistent
- New mechanics introduced in later scenes are introduced explicitly, not as surprises
5Sensory considerations
- Soft palette: avoid saturated reds, bright yellows, high-contrast flashing
- No autoplay sound
- All animations respect
prefers-reduced-motion
- All animations can be disabled in a settings panel
- No screen shake, no rapid camera movements, no flashing transitions
- WCAG 2.1 AA contrast minimum, but visual style should err calmer than that
6Indirection is the point
- Prompts ask about the Persona character's experience, not directly about the participant's
- Response options should not require the participant to label themselves ("I am anxious" is harder than "the character looks worried")
- Free-text fields have a small character cap to reduce demand burden
7No fail states
- There is no wrong answer
- There is no "try again"
- There is no "you missed something"
- The Guide character never expresses disappointment
What "engagement" should look like here
Engagement, in this tool, is the participant choosing to spend time with the material. It is not measured by completion. Two different success measures:
- Tool success: participants choose to engage with multiple scenes; skip rates suggest the low-demand framing is working; sessions are not abandoned in the first 60 seconds.
- Research success: the data captured is rich enough to answer the research questions.
A session where the participant skips most prompts but writes one rich free-text response is research-successful. A session where the participant clicks through every option but engages with none is tool-successful but research-poor.
Words that must not appear in user-facing copy
score
points
level up
achievement
complete
streak
combo
bonus
win
lose
fail
wrong
unlock
challenge
Words that should appear
Take a break
Stop here
That's okay
Whatever you'd like
Up to you
No need
When you're ready
The voice of the Guide character should sound like a calm, undemanding adult who has already accepted that the participant is in charge.