4.1 Quantitative analysis of the interface
The harmony of the world is displayed in morphology and numbers, natural philosophy, and poetry, they have the beauty of mathematics. --D 'Arcy Wentworth Thompson, On Growth and Form (1917)
An experienced interface designer, in the process of testing the new interface, the method of quantitative analysis can result in valuable results. One of the best quantitative interface analysis methods is the classic GOMS model.
4.2 GOMS Keyboard Model
4.2.1 Interface timing
Through a large survey, you can make a statistical to the time of the user's hyster, pointing, home, psychological preparation, and response during operation. For example, the keystroke time is 0.2 seconds, the pointing time is 1.1 seconds.
Double-click to be very difficult for some people, they often make two clicks or drag again. A good design should let all double-click operations can be implemented in additional ways (eg menus).
4.2.2 GOMS calculation
4.2.3 GOMS calculation example
This example illustrates what interface efficiency is the highest with the program interface that transforms each other with Fahrenheit. One criterion that improves interface efficiency is: Reduce useless operations. Useless operations include: Unnecessary mice clicks, dialog boxes useless (such as "Search.").
4.3 Interface efficiency measurement
The information efficiency of the interface is defined as the minimum amount of information required to complete the task divided by the information provided by the user actual needs.
4.4 Fitts Law and Hick Law
Fitts Law Description Users take the mouse how much time when pointing the mouse from a region to another area. Hick Law Instructions When the user needs to choose time between N optional actions.
