Predicting finger-touch accuracy based on the Dual Gaussian Distribution Model

Modelling the accuracy of finger-touch target acquisition is crucial for designing touchscreen UI and for modeling more complex and higher level touch interaction behaviors. Despite its importance, there has been little theoretical work on creating such models. Building on the Dual Gaussian Distribution Model [3], we derived an accuracy model that predicts the success rate of target acquisition based on the target size. We evaluated the model by comparing the predicted success rates with empirical measures for three types of targets: 1-dimensional vertical, 1-dimensional horizontal, and 2-dimensional targets. The predictions matched the empirical data very well: the differences between predicted and observed success rates were under 5% for 4.8 mm and 7.2 mm targets, and under 10% for 2.4 mm targets. The evaluation results suggest that our simple model can reliably predict touch accuracy.