01 / THE IDEA
What does it mean?
Time on task tracks the elapsed time required for a defined user task. It can reveal friction, but faster is not always better: high-stakes work may require deliberate verification.
02 / IN PRACTICE
Make it concrete.
Illustrative example: People take two minutes to complete a payment with the new checkout instead of four. Check that the faster flow has not increased payment mistakes.
03 / WHAT TO WATCH FOR
A common mistake.
Optimising for speed while ignoring accuracy and confidence.
04 / WHEN IT HELPS
When should you use it?
Alongside task success to examine efficiency without overlooking correctness.
05 / FURTHER READING
Explore the source.
Nielsen Norman Group — Usability Metrics ↗This is a reference for further learning, not an endorsement or a verbatim quotation.