Task Success Rate
The share of people who complete a task correctly.
Task success = completed ÷ attempted × 100
Why it matters
It is the most direct measure of whether a design works.
How to use it
- Define what success means before you test.
- Report it with a sample size.
- Pair it with the reasons people failed.
Example
If 41 of 50 people finish a transfer, the success rate is 82%.