Jan 14 2009

Usability testing – how many users should we test?

We often get asked the question – "how many users do we need to test our site on?", In most cases I really believe the ideal number is 5, current thinking is that it’s better to spend the usability budget on a number of rounds of testing by 5 users rather than say 1 test with more users.

Typically the first 3 users will find nearly all the biggest usability problems with the site (see: Jakob Nielson’s March 2000 article: ‘Why you only need to test with 5 users‘) – so keep the groups small and focus on finding and fixing the key usability problems.