Is feedback from 5 really enough?

In a notable study conducted by Jakob Nielsen back in 2000 he found that testing a “thing” with 5 users regularly uncovered about 80% of the usability problems with the “thing”. This finding has empowered researchers to feel good about much smaller sample sizes, especially when trying to work quickly and on a limited budget. What is important to remember about this guidance though is that it relates to uncovering usability problems. If you want to learn about market needs, customer preferences or get other feedback – not uncover usability problems – a larger number will be necessary to get valid insights.



https://www.nngroup.com/articles/why-you-only-need-to-test-with-5-users