Estimating Productivity: Composite Operators for Keystroke Level Modeling
Task time is a measure of productivity in an interface. Keystroke Level Modeling (KLM) can predict experienced user task time to within 10 to 30% of actual times. One of the biggest constraints to implementing KLM is the tedious aspect of estimating the low-level motor and cognitive actions of the users. The method proposed here combines common actions in applications into high-level operators (composite operators) that represent the average error-free time (e.g. to click on a button, select from a drop-down, type into a text-box). The combined operators dramatically reduce the amount of time and error in building an estimate of productivity. An empirical test of 26 users across two enterprise web-applications found this method to estimate the mean observed time to within 10%. The composite operators lend themselves to use by designers and product developers early in development without the need for different prototyping environments or tedious calculations.
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- 1.Card, S., Moran, T., Newell, A.: The psychology of human-computer interaction. Lawrence Erlbaum Associates, Hillsdale, NJ (1983)Google Scholar
- 2.Raskin, J.: The Humane Interface. Addison-Wesley, Reading (2000)Google Scholar
- 3.Baskin, J.D., John, B.E.: Comparison of GOMS analysis methods. In: CHI 1998 Conference Summary on Human Factors in Computing Systems, Los Angeles, California, United States, April 18-23, 1998, pp. 261–262. ACM, New York (1998)Google Scholar
- 7.John, B., Prevas, K., Salvucci, D., Koedinger, K.: Predictive Human Performance Modeling Made Easy. In: Proceedings of CHI 2004, Vienna, Austria, April 24-29, 2004, ACM, New York (2004)Google Scholar
- 8.Gong, R., Kieras, D.: A validation of the GOMS model methodology in the development of a specialized, commercial software application. In: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, CHII 1994, Boston, Massachusetts, pp. 351–357. ACM, New York (1994)Google Scholar
- 9.Haunold, P., Kuhn, W.: A keystroke level analysis of a graphics application: manual map digitizing. In: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, CHII 1994, Boston, Massachusetts, pp. 337–343. ACM, New York (1994)Google Scholar
- 10.John, B.: The Cog-Tool Project (2009), http://www.cs.cmu.edu/~bej/cogtool/ (accessed January 2009)
- 11.Maynard, H., Stegemerten, G., Schwab, J.: Methods Time Measurement. McGraw-Hill, New York (1948)Google Scholar
- 12.Zandin, K.: MOST Work Measurement Systems. Marcel Dekker, New York (1980)Google Scholar
- 13.Niebel, Freibalds: Methods, Standards, and Work Design. McGraw-Hill, New York (2004) Google Scholar
- 14.Mayhew, D.: Keystroke Level Modeling as a Cost-Justification Tool. In: Bias, Mayhew (eds.) Cost-Justifying Usability, 2nd edn., pp. 465–488 (2004)Google Scholar