Prototyping

Effective Graphical User Interfaces

Historical Methodology

In the past, it was very common for the consideration of the user interface to be one of the last steps performed in the System Development Life Cycle. Typically after everything about the system had been analyzed and designed, the user interface was developed. The driving factors behind the interface design tended to be what the programmer felt was a logical, intuitive depiction of the system's capabilities and processes. When, or if, usability testing was done, it generally occurred after barriers such as coding time and expense were in place that prohibited major revisions.

The focus of these analysis and design projects tended to be on utility, rather than usability. This has led to less than optimal interfaces being released. The results can be seen in the many instances where innovative products have initially failed after release and a system rewrite was necessary. See Relevant Cases for specific examples.

Reasons For Application Failure

: Product not approachable for the novice or less experienced computer user
: Sequence of keystrokes which seem incredibly obvious to the programmer are unknown or puzzling to the user
: No intuitive path, or clear indication to the user of what is required next and thus the user becomes frustrated at the lack of ability to perform the necessary task
: User learning curve and mental load requirements too high
: User finds product so difficult to use either refuses to use it or uses only a small fraction of its capabilities

User Considerations For Success

: Keep it simple (See Design Principles)
: Make it easy to learn
: Make it easy to navigate
: It should possess a coherent logic that the USER finds logical
: Don't waste the user's time - use an economical series of keystrokes to achieve an objective

To be able to accomplish this, a more structured approach to user interfaces must be put in place. The critical need for this is further emphasized when one considers that:

FROM THE POINT OF THE USER,
THE INTERFACE IS THE SYSTEM

The interface defines how the user and the computer will proceed to accomplish a task. Data has substantiated that a well-designed graphical user interface (See Design Principles) decreases the user's learning curve and is able to lessen the user's mental load when using the application. User interfaces have been shown to impact usability when measured by such criteria as speed, accuracy, number of tasks completed, time to learn how to use the system, frequence of reference to documentation, and subjective measures regarding satisfaction with system and satisfaction with performance.

It has been shown that when the System Development Life Cycle incorporates an iterative approach to analysis and prototyping of graphical user interfaces early in the project there is a much greater impact on usability. (See Relevant Cases) The bottom line results shows that considering the graphical user interface from the very beginning of a project results in what the user considers a better product and enhances the application's chances of success.

Key Methodology Factors in Developing the Graphical User Interface

Use a multi-disciplinary approach incorporating not only knowledge of design, programming, technology, and expert knowledge regarding the task, but also knowledge of people and their interactions

Use a structured approach that includes requirements definition, functional specification, prototyping, usability testing, and quality assurance testing

INVOLVE SYSTEM USER EARLY IN ANALYSIS EFFORTS BY MEANS OF ITERATIVE DEVELOPMENT AND RAPID PROTOTYPING

Early analysis should be dominated by collecting and synthesizing information about the user's needs through requirements analysis, task analysis, and usability tests (See Prototyping)

Use user interactions and collected information to continually improve the system interface

Remember to use basic design principles when prototyping graphical user interfaces

Analysis and Prototyping

The goal of applying analysis and prototyping methodology regarding the graphical user interface early in the development life cycle is to be able to produce the most reasonable interface within practical business constraints. This occurs by being able to eliminate or revise features and exploit easily supported functionality with limited commitment in terms of time and capital invested. Another critical result of early analysis and prototyping is the data that early analysis provides. This data provides the analyst with the information necessary to be able to assess which features are critical to the usability or future enhancement path of the application.

Benefits To Early Analysis And Prototyping Of Graphical User Interface

Keeps ultimate product vision in sight

Give ability to define base functionality required which cannot be compromised

Gives ability to distinguish between features that are critical and shape the product's future and those features that can be dropped or added incrementally after release

By developing rapid and disposable prototypes rather than time consuming code, avoid management feeling committed to use after expending resources

With ability to discuss interface behavior with developers implementing each feature, can avoid misinterpretation or oversights by managers and developers

Allows clarification of details missing from functional specification and resolution of design problems before implementation

Can develop release criteria that allow decisions to be made regarding added functionality, interface design tradeoffs, and whether product ready to be released

Can establish minimum and target goals for specific criteria

Relevant Cases

What Is Prototyping?

Design Principles

References

URL: http://www.umsl.edu/~sauter/analysis/prototyping/intro.html
Project Team Members: C. Melissa Mcclendon, Larry Regot, Gerri Akers