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Usability Evaluation of Randomized Keypad

Young Sam Ryu, Do Hyong Koh, Brad L. Aday, Xavier A. Gutierrez, and John D. Platt

Journal of Usability Studies, Volume 5, Issue 2, Feb 2010, pp. 65 - 75


In this work, the usability of a randomized numeric keypad was examined and compared to the usability of a conventional numeric keypad. The comparison used completion time measurements and the error rate of short (4 digit) and long (8-digit) PINs to contrast efficiency and accuracy of the keypads. The results showed that the average completion time with a randomized keypad is longer than with a conventional keypad. Additionally, the number of errors with a randomized keypad was significantly higher than with a conventional keypad, particularly when using long PINs. Accordingly, a randomized numeric keypad is more applicable to tasks with short (4-digit) PINs.

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Usability Evaluation of Randomized Keypad