urTRACE Variables add real, recordable behaviour on top of your design - the interactive pieces a prototype can't produce by itself. Draw over the element you want to activate, and the Variable takes on that element's look, so a designed field or switch becomes genuinely usable.

Any Variable can be made required (the tester must complete it before moving on - a working login or form gate), checked against an expected value, or set to branch testers to a different screen based on their choice.

Keep functionalities separate. Give each interactive element its own region - don't stack two Variables on the same spot, or nest one inside another (a dropdown sitting inside a text field, for example). Overlapping controls compete for the same taps and blur what you're measuring.

Don't Duration 30 min 2 hours Select boxes

A Variable dropped on top of a slider. The two controls fight for the same taps, so the heatmap and results can't tell which one the tester meant.

Do Duration Variable Just me 2-4 people

Give each control its own region. Every tap measures one thing, and each Variable reads cleanly on its own.

Keep functionalities separate - don't stack a Variable on an existing control.