Models and Theories in Human-Computer Interaction/GOMS & its drawbacks

Analysis of GOMS model

GOMS basically, “a model of user performance that also centers around user goals and actions is the goals, operators, methods, and selection rules (GOMS) model developed by Card, Moran, and Newell (1983) and extended by Kieras (1988a).” Goals are what the user is trying to accomplish in a given task for example unlocking a cell phone screen. To accomplish this goal using the ‘click/press key’ would be the example of operator. Methods are sequences of operators and sub-goals that accomplish a goal for example to set up a password steps may include the following steps 1. Select lock screen setting, 2. Select screen lock option, 3. Entering the old PIN, 4. Choosing an option among None/ Swipe/ Face Unlock/ Pattern/ PIN/ Password, 5. Set new desired password option, 6. Confirming new password, 7. Click done button. Selection rules implies which method should be picked to satisfy a particular goal, as there are different options to reach the same goal. The user can select any option among None, Swipe, Face Unlock, Pattern, PIN and Password depending upon their desired security level and knowledge. GOMS model is very practical in the case where the user have many ways to accomplish the same goal.

However “evaluation of the GOMS structure reveals problems such as too many methods for accomplishing a goal, similar goals supported by inconsistent methods, and methods that rely too heavily on long-term memory (e.g., see Gong & Kieras, 1994).” GOMS model also failed to address user behavior, biological, or organizational factors into account.

References:

1. Wickens, C., & Gordon, S. (2004). An introduction to human factors engineering (2nd ed.). Upper Saddle River, N.J.: Pearson Prentice Hall.

2. Gong, R., & Kieras, D. (1994). A Validation of the GOMS Model Methodology in the Development of a Specialized, Commercial Software Application. In Proceedings of CHI, 1994, Boston, MA, USA, April 24-28, 1994. New York: ACM, pp. 351-357.