Whether Moving or Not: Modeling and Predicting Error Rates in Pointing Regardless of Target Motion.

Understanding the mechanism by which a user's error rate changes in point-and-click tasks is essential to enhance the usability of various interactions such as typing, gaming, and playing digital instruments. The most well-known explanation for this problem is the inverse relationship between the movement time and the pointing error rate, called the speed--accuracy trade--off. However, recent studies have shown that movement time is not an optimal indicator to explain the change in user's pointing error rate. They also have limitations that can only predict error rates for fixed targets. Based on perceptual control theory and the recent model of moving target selection, this study presents a novel model that accurately predicts pointing error rates regardless of target motion. In two user studies on fixed and moving targets, the model explains the observed error rate with a high coefficient of determination. This allows various interactions that were not previously possible.