Part of the GOMS family of predictive models, the Keystroke-Level Model GOMS (KLM-GOMS) is a quantitative modeling tool for predicting how long it will take expert users to complete a specific task with no errors.
KLM-GOMS predicts task times based on a simple set of physical and mental operators including keystrokes, button clicks, pointer movement, keyboard to mouse movement, and thinking time. Each KLM operator is assigned a time based on empirical research. To obtain the predicted time for a task, you add the times for individual operators.
Sources and contributors:Ben Werner, Chauncey Wilson.