The Effects of Recognition Accuracy and Vocabulary Size of a Speech Recognition System on Task Performance and User Acceptance

Abstract

The purpose of the present study was to determine the effects of recognizer accuracy and vocabulary size on system performance of a speech recognition system. Subjects, ranging in age from 20 to 55 years, performed a data entry task using a simulated speech recognizer which simulated three accuracy levels and three levels of available vocabulary. Task completion times and subjective measures of acceptability were recorded. Results indicated that the accuracy level at which the recognizer was performing significantly influenced the task completion time and the user's acceptability ratings. Vocabulary size also significantly affected task completion time, however, its affect on the acceptability ratings was negligible. Older subjects in general required longer times to complete the tasks, however, they consistently rated the speech input systems more favorably than the younger subjects.

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