LAUSR

When developing applications, User Interfaces (UI) are considered as an important and integral component of any application.  With badly designed UI, users are less likely to use the application, leading to low adoption rates and is not desirable in any application development setting.  The process of developing good intuitive and stream-lined UI for users is complex, that requires many processes and experts from many fields to contribute.  When evaluating potential UI designs, there are many attributes and features that could be examined either in a qualitative and/or quantitative standpoint.  The Updated Goals, Operators, Methods, and Selection Rules (GOMS) model is an approach that has been used in the area.  With the Keystroke Level (KLM) extension, it is possible to quantitatively estimate the time requirement or efficiency of UI for completing different tasks with minimal effort, and has been adopted in many GUI improvement projects.  Due to the usefulness, extensions to the GOMS model had been proposed over the years including extensions to account for motion control interfaces.  Though the GOMS model has been useful for quantitatively evaluating UI design, the main input device of modern smartphones and tablets are touch screens, which are different in nature when compared to traditional computer inputs.  The differences leads to the point that GOMS model with KLM is ill-suited for touch screen based applications.  This research paper addresses the issue by proposing extensions to the GOMS model to account for UI that are based on touch screen input devices.