Human factors and interface improvement

According to Hiltz and Johnson’s studies (1990), high scores on “Interface”

correspond to high satisfaction with the system interface. The primary components are finding the system to be: understandable, courteous, and not distracting easy to learn, friendly rather than impersonal, not frustration; and, overall, a “good” system rather than a “bad” system. …Interface is concerned with a task orientation and a CMCS as primarily a computer system; however, since the task is communication, technological factors do not dominate its determination quite so strongly. Communications process variables (the content of what other humans do on the system) are much more important for determining perceptions of overall system performance of productivity

than they are in influencing interface satisfaction.

There are several conceptualizations of usability design heuristics and best practices that are widely used. The most pervasive is a set of user interface design principles that were elucidated by Nielsen (1994), based on a principal components analysis of the usability problems found in a number of studies of various user interfaces. These design principles are summarized as follows:

• Visibility of system status. The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

• Match between system and real world. The system should speak the users’

language, with words, phrases, and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

• Error prevention. Even better than a good error message is a careful design which prevents a problem from occurring in the first place.

• User control and freedom. Users often choose system functions by mistake and will need a clearly marked “emergency exit” to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.

• Consistency and standards. Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

• Recognition rather than recall. Make objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

• Flexibility and efficiency of use. Accelerators—unseen by the novice user—may often speed up the interaction for the expert user to such an extent that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.

• Aesthetic and minimalist design. Dialogues should not contain information that is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.

• Help users recognize, diagnose, and recover from errors. Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.

• Help and documentation. The ideal system can be used without documentation, but it may often be necessary to provide help and documentation. Any such information should be easy to search, focused on the user’s task, list concrete steps to be carried out, and not be too large.

Also, there are many general principles for design of human-computer interfaces apply to the design of e-commerce environments (Helander et al., 1997). Examples include:

z Simplicity: Do not compromise usability to gain function.

z Support: User should be in control with proactive assistance.

z Visibility: Make objects visible and intuitive to control.

z Reversible action: Make actions reversible.

z Feedback: Provide visible (or auditory) feedback on all user actions.

z Accessibility: Make all objects accessible at all times.

z Personalization: Allow the user to customize the interface.

Elements of the visual should fit together in an aesthetic and harmonious relationship in a manner which is interesting but not distracting (Pettersson, 1999).

The goal in information design should be clarity of communication. The following Table 2.3 presents some points summarized by Pettersson that how interface should be designed to get attention in several categories.

Table 2. 3 Different methods to get attention

Text Color

z Set text large enough.

z Set text bold enough.

z Set headings in different type versions to aid comprehension of the text content.

z Use space and the actual placement of a heading to enhance the hierarchic structure.

z Make the key words red or underline them.

z Use headings, italics, boldface, or a larger font to highlight the relevant information.

z Do not overuse accenting techniques in text.

z Use blinking and flashing text on a computer screen as an accenting technique.

z Use bright and bold colors to capture attention.

z Use color to clarify the structure of a text. Certain parts of the text may be printed with colors or printed on top of backgrounds in different colors.

z Consider embedded meanings of different colors when using colors to accent words in a text.

z Use color coding to improve attention.

The number of color codes should be limited and they should always be explained.

z The number of colors simultaneously for the “default color set,” and not more than six colors for visual search, for color images and for color

interpretation from memory.*

Pictures Layout

z Use pictures of the human figure, in particular the face.

z Use picture elements that are large enough to see.

z Make the most important part of the subject large and clear.

z Use picture elements that are bold enough.

z Use several kinds of visual types, such as diagrams, drawings, photos to increase interest in a material.

z Pictures must be in color so they resemble the real world.

z Put pictures between the appropriate paragraphs in the text to get maximum impact

z Use bullets, arrows, icons, underlining, margin notes, repetition, and/or white space to highlight the relevant

information.

z Use arrows in order to draw attention to a picture

z Use lines in various colors in order to draw attention to a picture or to specific picture elements.

z Write a legend for each picture.

Balance

z Use unexpected, irregular, and unstable design to attract attention.

z Provide a good contrast between figure and ground

z Use combinations of dark and bright, large and small, round and square, to sharpen meaning

* Add by researcher. (Aarås, Horgen, Bjørest.Ro and Thoresen, 1998).