How many test users in a usability study?

Fresh in from our favourite usability guy:

http://www.useit.com/alertbox/number-of-test-users.html

Tl;dr – 5 is the optimal. As you add more users, you spend more time observing same findings per new insight gained. If you just want stats, test at least 20 so the maths look good. For card sorting, test 15 or more. When eyetracking, test 39 to account for individual variations.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s