IS 401 Ch. 7 Flashcards
A key step in systems design
is to classify the inputs and outputs for each event
as either a system interface or a user interface.
System interfaces
are inputs and outputs that require minimal human intervention.
They might be inputs captured automatically by such special input devices as scanners, electronic messages to or from another system, or transactions captured by another system.
Many outputs are considered system interfaces if they primarily send messages or information to other systems (e.g., a pickup notification to a shipping company) or if they produce reports, statements, or documents for external agents or actors without much human intervention (e.g., end-of month credit card statements e-mailed to cardholders).
User interfaces
are inputs and outputs that more directly involve a system user. User interfaces can be for internal or external users. Their design varies widely depending on such factors as interface purpose, user characteristics, and characteristics of a specific interface device. For example, although all user interfaces should be designed for maximal ease of use, other considerations, such as operational efficiency, may be important for internal users who can be trained to use a specific interface optimized for a specific hardware device (e.g., a keyboard, a mouse, and a large high-resolution display). In contrast, a quite different user interface might be designed for a customer-facing system that assumes a cell phone as the input/output device.
Understanding the User Interface
Many people think the user interface is developed and added to the system near the end of the development process, but the user interface is much more important than that. It is everything that the end user comes in contact with while using the system—physically, perceptually, and conceptually. From a user perspective, the user interface is the entire system. The programs, scripts, databases, and hardware behind the interface are irrelevant.
physically
desk, chair, light, keyboard, mouse, touchscreen, keypad
perceptually
colors, shapes, textures, fonts, sounds, speech, windows, menus, buttons
conceptually
customers, partners, friends, orders, shipments, inquiries, feedback, ratings
user-centered design
design techniques that embody the view that the user interface is the entire system
emphasizes three important principles:
- Focus early on the users and their work.
- Evaluate designs to ensure usability.
- Use iterative development.
Focus early on the users and their work.
User-oriented analysis and design tasks are performed as early as possible and are often given higher priority than other tasks.
For example, such user-oriented analysis tasks as stakeholder identification and interviews occur early in the project. User interfaces are designed in early iterations, and user-related design decisions drive other design decisions and tasks.
Usability
refers to the degree to which a system is easy to learn and use.
Evaluate designs to ensure usability.
Ensuring usability isn’t easy; there are many different types of users with different preferences and skills. Features that are easy for one person to use might be difficult for another.
For example, if it is too flexible, some end users might feel lost. On the other hand, if the interface is too rigid, some users will be frustrated.
Ease of learning and ease of use are often in conflict. For example, menu based applications with multiple forms, many dialog boxes, and extensive prompts and instructions are easy to learn; indeed, they are self-explanatory. And easy-to-learn interfaces are appropriate for systems that end users use infrequently.
But if internal users use the system all day, it is important to make the interface fast and flexible, with shortcuts, hot keys, voice commands, and information-intensive screens. This second interface might be harder to learn,
but it will be easier to use after it is learned. Internal users (with the support of their managers) are willing to invest more time learning the system in order to become efficient users.
Developers employ many techniques to evaluate interface designs to ensure usability. User-centered design requires testing all aspects of the user interface. Some usability testing techniques collect objective data that can be statistically analyzed to compare designs. Some techniques collect subjective data about user perceptions and attitudes. To assess user attitudes, developers conduct formal surveys, focus group meetings, design walk-throughs, paper-and-pencil evaluations, expert evaluations, formal laboratory experiments, and informal observation.
Use iterative development.
doing some analysis, then some design, then some implementation, and then repeating the processes. After each iteration, the project team evaluates the work on the system to date. Iterative development keeps the focus on the user by continually returning to the user requirements during each iteration and by evaluating the system after each iteration.
metaphors
analogies between features of the user interface and aspects of physical reality that users are familiar with
Direct manipulation metaphor
Manipulating objects on a display that look like physical objects (pictures) or that represent them (icons)
EX: The user drags a folder icon to an image of a recycle bin or trash can to delete a collection of files.
Desktop metaphor
Organizing visual display into distinct regions, with a large empty workspace in the middle and a collection of tool icons around the perimeter
EX: At computer startup, a Windows user sees a desktop, with icons for a clock, calendar, notepad, inbox and sticky notes (the computer interface version of a physical Post-It note).
