Usability & User Interface Design Explained

The purpose of this document is to create a methodology to create an effective user interface.

Without attention to usability users are less productive, products take more time to develop, require more training and support, and are less attractive to customers.

A User-Centric Design Approach

"A well-designed user interface is based on principles and a development process that centres on users and their tasks." (Microsoft Corporation, 1995)

Only the users know what they need and what they want; and the only way to find out what the users need and want is to ask the users.

Human Factors Goals

Human Factors Engineering is based on 3 goals:

1. Provide an interface that is intuitive to the users - create an interface that users can readily understand
2. Provide the user with the easiest interaction possible - make it easy for the users to get their job done
3. Help the users complete their tasks - make it really easy

User Interface Design Principles

• Consistency
• Redundancy
• Using multiple cues increases the likelihood of retention. For example, when an error occurs, pop up a dialog and make the "beep" sound.
• Every menu item and button should be accessible by keyboard.
• Every mouse action should have a keyboard equivalent.
• Forgiveness
• Enabling buttons only when appropriate and prompting before committing actions provide reminders to users about the effects of their choices.
• Allow users to back out of or undo actions, especially those that are destructive.
• Feedback
• Every action that the user performs should provide some feedback immediately.
• Feedback can be visual, audio, or both.
• Double-check destructive actions before they are committed.
• Simplicity
• An easy way to make an interface intuitive is to keep it simple.
• Avoid distracting the users with unnecessary information.
• Interaction
• Allow the users to personalise the system. Where appropriate, lets the users customise settings such as defaults, colours, fonts, and options.
• Directness
• Allow users to directly manipulate the objects of the interface, providing actions such as drag-and-drop.

User Interface Design Methodology

• User Identification
• Task Analysis
• Understand 'what' users do and 'how' they do it
• Create User Interface Design Guide
• Project background - users, tasks, assumptions
• Design guidelines - sizes, colours, menus, widgets
• Appendices - questionnaire results, glossary
• Create User Interface Design
• Design, prototype, and test
• Usability Testing
• Can be as easy as a computer, a user, and an observer. Do they understand the interface? Can they perform their tasks easily? Do they keep making errors?

Excerpts taken from 'User Interface Design Explained', Douglyss Giuliana.