By Christine Perfetti and Lori Landesman Originally published: Jun 18, 2001 One of the most popular questions we hear from web designers and usability professionals is: "How many users is enough when conducting usability tests?" Until recently, we had believed -- and told our clients -- that it wasn't usually necessary to test with more than eight users.
In 2009, ModCloth founder Susan Gregg Koger launched her site's "Be the Buyer" program. It mixes business with pleasure. ModCloth buyers receive excellent data on what garments to buy and, at the same time, get to indulge in their fantasy of being a store buyer.
Over the past 3 days I attended the Internet Retailers Mobile Commerce Forum, where the week's events were filled with insightful and useful information presented by some of the world's leaders in mobile commerce.
Jakob Nielsen's Alertbox, June 26, 2006: We can define usability in terms of quality metrics, such as learning time, efficiency of use, memorability, user errors, and subjective satisfaction. Sadly, few projects collect such metrics because doing so is expensive: it requires four times as many users as simple user testing.
Often we are faced with determining the appropriate number of participants for our usability tests. Too many participants increase the cost and development time. If the number of participants is too small, the testing process may fail to detect important problems and result in reduced site usability.
Question: How many users do you need to test with for a usability test? Answer 1: = 5 users (Jakob Nielsen and Thomas Landauer, 1993). Answer 2: = 15 users (Laurie Faulkner, 2004), PDF file. So, which is it, 5 or 15?
Originally published: Apr 01, 2003 Not so very long ago, it was agreed that five to eight users was enough for a good usability test. Somehow, this idea achieved mythic status. We believed it. We preached it to everyone who would listen.