Usability Testing – guide and stats

Who should we ask to test our design? Should that be an experts or rather novices? In 1992 Jakob Nielsen (born 1957 in Copenhagen, Denmark, a leading web usability consultant) made an experiment, in which he used three groups of evaluators: Novice, Double and Double.

  • Novice – no experience in usability engineering
  • Regular – general usability specialists
  • Double – specialists in particular subject of an experiment

It was found that:

  • The novices found 22% of the usability problems
  • The regulars found 41%
  • The doubles found 60%

Nielsen concluded also that:

  • Group of 5 novices would find 50% of the usability problems
  • 5 regular specialists would find about 80%
  • 5 double specialists would find 98% of the problems