Learning gaze typing: What are the obstacles and what progress to expect?

Gaze interaction is a promising input modality for people who are unable to control their fingers and arms. This paper suggests a number of new metrics that can be applied to the analysis of gaze typing interfaces and to the evaluation of user performance. These metrics are derived from a close examination of eight subjects typing text by gazing on a dwell-time activated onscreen keyboard during a seven-day experiment. One of the metrics, termed "Attended keys per character", measures the number of keys that are attended for each typed character. This metric turned out to be particularly well correlated to the actual numbers of errors committed (r = 0.915). In addition to introducing metrics specific for gaze typing, the paper discusses how the metrics could make remote progress monitoring possible and provides some general advice on how to introduce gaze typing for novice users.