During his keynote address at the UX Conference in London, usability expert Jakob Nielsen was asked what is better: conduct a large usability study or small usability studies.
In his reply, Nielsen explained you will learn a lot from a study with a large number of users.
However, the return on investment goes down with the more people you have in your studies.
He explained you’ll learn more from having multiple studies with a small number of users, say three people, than with one usability study with a large number of users.
The reason? With a small number of users, you can change the design quickly, and test again.
Instead of conducting one usability study with 100 users, his recommendation is you conduct 33 studies with three users each, and improve the design each time.
But don’t take my word for it. Listen to what Jakob Nielsen has to say in this two-minute video.
