The Keystroke-Level Model

The Keystroke-Level Model is a specific framework that can predict the time associated with a task based upon a specified scenario. Within the framework, the user is provided a sequence list of actions that they must perform and then the times associated with the actions are added up. When implementing the KLM, it is not necessary to create a design as the framework only requires minimal accessibility standards in that the user interface is precise and detailed enough in order for the sequence to be properly executed. Actions within this framework are identified as keystroke level if they are certain types such as the movement of a mouse or actual key pushing rather than a simple system login. Moreover, within the framework there are actions referred to as operators. Under the KLM, certain actions are standard with regard to execution times (Card, Moran & Newell, 1983; Kieras, 1993).

The Keystroke-Level Model per Lane et al. (1993) noted that the framework has two specific parameters: K and M. K is noted as the time that it takes to press a single key on a computer keyboard; while M is expressed as the amount of time it takes mentally for a command. It is essential that such distinguishing occurs for the purposes of this discussion between time and mental preparation of command. When examining the difference between the two, it is more or less the operation of mental preparation rather than the contemplation of the operation. The framework is specific in that the first keystroke in the name of a command contains the letter M, while any subsequent letters in the name of the command do not (i.e. SUM).

The Keystroke-Level Model is viewed as a simplification of the GOMS focusing solely on tasks and operations at a miniscule level. Card et al. (1983) added that the physical operations that are performed by users are K for keystroking, B for pressing the button on the mouse, P for either moving or pointing the mouse, H for switching hands from keyboard to mouse and then from mouse to keyboard, D for using the mouse to draw lines, M for the mental preparation of a specific action and R for response by the system. Each specific task as aforementioned is broken down into a sequence of the operators (John & Kieras, 1996).

Holleis et al. (2007) further added that the Keystroke-Level Model presents definitive results in accurate handling input and overall operation of the selection of heuristics. The use of Keystroke Level Modeling is primarily based on numerous decades of intense research on human interaction with software. The approach has proved to be efficient when comparing products and/or designs to be implemented into a network's policies and strategies. Respective computer users can obtain training on the model. The model is so precise that it will generate estimations at the millisecond level and can offer definitive task time operations. Users of the Keystroke-Level Model can benefit tremendously in better understanding and ascertaining operations and tasks. (Card, Moran & Newell, 1980; Jonassen, Tessmer & Hannum,1999).

Hence, computer environments can benefit tremendously from simplified frameworks of operations in terms of user education on devices and/or systems. Essentially, the framework is a mechanism that can be break down specific components of a task into minute details that make it easier for the computer user to comprehend mentally.

References

Card, S. K., Moran, T. P., & Newell, A. (1980). The keystroke-level model for user performance time with interactive systems. Communications of the ACM, 23(7), 396-410.

Card, S. K., Moran, T. P., & Newell, A. (1983). The Psychology of Human-computer Interaction. East Sussex, UK: Psychology Press.

Holleis, P., Otto, F., Hussmann, H., & Schmidt, A. (2007). Keystroke-level model for advanced mobile phone interaction. Proceeding CHI '07 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, 1505-1514. doi:10.1145/1240624.1240851

John, B. E., & Kieras, D. E. (1996, December). Using GOMS for User Interface Design and Evaluation: Which Technique? ACM Transactions on Computer-Human Interaction, 3(4), 287-319.

Jonassen, D. H., Tessmer, M., & Hannum, W. H. (1999). Task Analysis Methods for Instructional Design. East Sussex, UK: Psychology Press.

Kieras. (1993). Using the Keystroke-Level Model to Estimate Execution Times [Article]. Retrieved from University of Michigan website: http://www.pitt.edu/~cmlewis/KSM.pdf

Lane, D. M., Napier, H. A., Batsell, R. R., & Naman, J. L. (1993). Predicting the Skilled Use of Hierarchical Menus With the Keystroke-Level Model. Human Computer Interaction, 8, 185-192.