where to use GOMS
I could see GOMS being used for a cash register UI for cashiers. The operations, methods etc. are very clearly defined and finite. The users are expert users, since they use their cash registers for a large part of their workday. Finally, operation timings are not that variable since the operations are so small and atomic. Adding a new item type or step in the checkout process would fit well into the GOMS model and be clearly measurable in how much time it adds.
I would not use GOMS for an interactive kiosk at a tourist destination. Since they are tourists, they would likely be using the kiosk for the first time and would not be expert users. In addition, the timing would not matter as much since a tourist can afford to lose a couple of seconds using a UI, versus a cashier, who uses the cash register so often that a few seconds can become large losses in productivity.
