CS252. User Interface Design

Solutions to Homework 1 - Chapter 2 in Jordan book

2. Compare and contrast effectiveness, efficiency, and satisfaction by giving examples of each from your experiences with software interfaces.

Effectiveness is characterized by the ability to complete some user goal, efficiency by the number of steps or amount of time needed to complete the necessary tasks for accomplishing that goal, while satisfaction can be achieved only if the way of accomplishing the goal is acceptable within the context of the user's work environment. Examples should emphasize the differences between the three criteria, such as the following.

Type of Software Effectiveness Efficiency Satisfaction
Word Processing Ability to create an index for a complete book manuscript. Number of mouse clicks needed to insert an indexing point. How easy it is to learn and apply the actions needed to create an index of both categories and subcategories.
Spreadsheet Ability to create a new spreadsheet that is similar to another one, but with some slight modifications. How long it takes to find the location of a error when one of the formulas is changed. Whether the printed spreadsheet looks like the kind the user's company requires.

6.Why do menu-based interfaces provide better guessability than command-line interfaces?

To enter commands, the user must "recall" what the names of the commands are and select an appropriate one; he/she may also have to remember how many arguments there are, in what order they should be used, etc. A menu-based interface lays out the options, so that the user only has to "recognize" the appropriate action.

10.Is each of the following examples from word processing software a test of effectiveness, or of efficiency? Justify each answer.

  1. Number of keystroke and mouse movements needed to copy a section of text
  2. Ability to change page margins
  3. Maximum limit on the size of document files
  4. The fact that the computer must be rebooted in order for changes in default settings to take effect
  5. Availability of a feature to sum up the numbers in a table's columns

2, 3, and 5 describe effectiveness issues, since they support (or limit) the goals that a user can accomplish. 1 and 4 are questions of efficiency, since they affect the amount of time or effort that must be spent to carry out individual tasks.