Pair-wise variability index: Evaluating the cognitive difficulty of using mobile text entry systems

Abstract

A modified pair-wise variability index for evaluating the cognitive difficulty of using mobile text entry systems is proposed. The index is easy to compute from keystroke logs acquired from typing experiments where keystroke times are recorded. The effectiveness of the pair-wise variability index is demonstrated on the keystroke logs acquired using three different text entry strategies. © Springer-Verlag Berlin Heidelberg 2004.