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Task success rate 0:35
A 35-second explainer of Task success rate, narrated over the same demo you can try yourself.
Try the interactive Task success rate demo
What this video covers
Task success rate is the share of people who finish a task - four of five users complete it, so 80%. It is the most basic measure of whether a thing works at all, and the easiest to read too much into.
With five users, one person flipping from fail to pass swung the score twenty points. With twenty, the same flip barely moved it. The number didn't get more honest when it got more stable - it just stopped lying so loudly. A success rate without a sense of its sample size is a confident-looking guess.
