Design memo: why tasks have par instead of timers

Design memos document real decisions in Wiz Kids and the research behind them.

Wiz Kids tasks are scored like golf, not like a race: a task carries a par — the efficient solution's cost in the task's own currency (blocks for a charm, edits for a video cut, steps for a file errand) — and stars compare your solution's cost to par. Three stars at par or better, two within a grace band, one for done-at-all. There is no timer anywhere in the product. This memo is why.

Why not timers

The case against clocking children assembles itself from evidence this library already carries: speed pressure produces racing errors, and errors practiced are errors learned — accuracy-first is our typing doctrine precisely because fluency compounds from correctness, not haste. Test-pressure anxiety is real and unevenly distributed, and a countdown converts a puzzle into a threat for exactly the children we most need to keep in the game. Deeper still: a timer measures the child; par measures the solution — and only one of those framings survives contact with motivation research. "Your plan took 9 blocks; it can be done in 6" invites another attempt at an artifact; "you were too slow" is a verdict on a person. Same information, opposite psychology — the no-leaderboards logic applied to the time axis.

What par rewards instead

Par pays for planning and elegance: seeing the repeat in four identical moves, choosing the two-key chord over the four-click menu route, the shorter path through the folder tree. That's the actual curriculum — computational thinking's find-the-pattern move, the shortcut argument — expressed as a score. And because retries are unlimited and unpunished (runs are free; experimentation is the method), missing par isn't failure, it's the game saying there's a better solution in here — a desirable difficulty with the difficulty in the puzzle, not in the pressure.

Keeping par honest

A par a child can't actually meet is a broken promise, so par is a verified claim wherever we can make it one: for stepwise navigation charms our validator proves par equals the BFS-shortest path through the world; where loops and functions make "shortest" a design judgment, par is the authored reference solution, simulated before commit. The grace band (two stars within par+2) absorbs legitimate solution diversity, and the third star asks for efficiency, never perfection-plus-luck.

The failure mode we watch

Par has its own dark side: star-chasing — a child re-grinding a solved task for the missing star past the point of learning. Two guards: the stars are mastery signals, not currency (nothing purchasable hangs on them), and once a lesson is fully starred its card stops asking — completed work reads as complete, because a game that keeps soliciting perfection from finishers has quietly become a retention mechanic, and we've written down which side of that line we build on.

References

• Card, S. K., Moran, T. P., & Newell, A. (1983). The Psychology of Human-Computer Interaction — solutions have measurable costs; the intellectual license for par.
• Ryan, R. M., & Deci, E. L. (2000). Self-determination theory. American Psychologist, 55(1) — competence feedback vs controlling evaluation, the timer/par distinction in theory form.
• Bjork, R. A., & Bjork, E. L. (2011). Making things hard on yourself, but in a good way. — difficulty belongs in the task, not the clock.

© Glu IO Pty. Ltd. — Wiz Kids (wiz.kids). Link freely; republication requires permission — see terms. Found an error in our reading of the research? We correct fast: tell any teacher piloting Wiz Kids.