NEM: "novice expert ratio method" a usability evaluation method to generate a new performance measure

ABSTRACT

NEM is a new evaluation method that generates a quantitative measure in terms of the usability of any specific system. In this method, at each step of the operational procedure in the situation of the usability testing, the ratio of time required for a novice user to that of an expert user is used to generate an NE ratio. The time required by the expert user is thought to represent the minimum time to operate the system. Hence, regardless of the absolute amount of time required by the user, the magnitude of the ratio can be regarded as a measure to represent the difficulty in using that system for the novice user. By applying this method to the evaluation of the car navigation system, it was confirmed that this method is quite useful in identifying the procedural step that has a usability problem.

REFERENCES

• 1: Norman D. A.: The Psychology of Everyday Things. Basic Books (1988)
• 2: Stuart K. Card , Thomas P. Moran , Allen Newell, The keystroke-level model for user performance time with interactive systems, Communications of the ACM, v.23 n.7, p.396-410, July 1980 [doi>10.1145/358886.358895]

INDEX TERMS

Keywords:
expert user, keystroke level model, novice user, task performance measure, usability evaluation