GOMS stands for Goals, Operators, Methods and Selection rules.It is an approach to Human Computer Interaction observation developed by card, moran and newell in 1983.
Goals represent the goal that the user is trying to achieve
Operators are the set of automatic-level operations with which user use's to attain the goal.
Methods represent the sequence of operations grouped together toattain a goal.
Selection rules it is used to decide which method to use when several are applicable for solving a goal.
Variations of GOMS: