Various Authors - The Smashing Book

What is user interface design? What makes a user interface effective, and, more importantly, how do you go about crafting a good user interface? This chapter looks at the theory as well as the practical techniques involved in visual interface design in modern Web applications.

The way that you accomplish tasks with a product what you do and how it responds thats the interface Jef Raskin

User interface design isnt just about buttons and menus; its about the interaction between the user and the application or device, and in many cases, its about the interaction between multiple users through that device. This means that user interface design isnt about how a product looks, but rather about how it works. Its not just about arranging buttons and picking colors, but rather about choosing the right tools for the job. Does a particular interface even need buttons? If so, what do those buttons need to do? What do I need to provide users with so that they can figure out how my application works and accomplish what they want to do with ease?

Working on the user interface early on in the product development life cycle is vital because, as Jef Raskin succinctly puts it, As far as the customer is concerned, the interface is the product. The user sees and interacts with the user interface, not the underlying back-end architecture of your application. Getting this element right will thus have a big impact on how much your customers enjoy using your product and how easy your product is to use. Start by designing the interface first and then coding the back-end engine that powers it, rather than building the back-end first and then putting an interface wrapper over top.

Before we proceed to build a user interface for our product, its important to first understand what makes a good user interface; what are the qualities we should aim to achieve? All great interfaces share eight qualities or characteristics:

Clarity : The interface avoids ambiguity by making everything clear through language, flow, hierarchy and metaphors for visual elements. Clear interfaces dont need manuals. They also ensure users make less mistakes while using them.

Concision : Its easy to make the interface clear by over-clarifying and labeling everything, but this leads to interface bloat, where there is just too much stuff on the screen at the same time. If too many things are on the screen, finding what youre looking for is difficult, and so the interface becomes tedious to use. The real challenge in making a great interface is to make it concise and clear at the same time.

Familiarity : Something is familiar when you recall a previous encounter youve had with it. Even if someone uses an interface for the first time, certain elements can still be familiar. You can use real-life metaphors to communicate meaning; for example, folder-style tabs are often used for navigation on websites and in applications. People recognize them as navigation items because the metaphor of the folder is familiar to them.

Responsiveness : This means a couple of things. First, responsiveness means speed: a good interface should not feel sluggish. Secondly, the interface should provide good feedback to the user about whats happening and whether the users input is being successfully processed.

Consistency : Keeping your interface consistent across your application is important because it allows users to recognize usage patterns. Once your users learn how certain parts of the interface work, they can apply this knowledge to new areas and features, provided that the user interface there is consistent with what they already know.

Aesthetics : While you dont need to make an interface attractive for it to do its job, making something look good will make the time your users spend using your application more enjoyable; and happier users can only be a good thing.

Efficiency : Time is money, and a great interface should make the user more productive through shortcuts and good design. After all, this is one of the core benefits of technology: it allows us to perform tasks with less time and effort by doing most of the work for us.

Forgiveness : Everyone makes mistakes, and how your application handles those mistakes will be a test of its overall quality. Is it easy to undo actions? Is it easy to recover deleted files? A good interface should not punish users for their mistakes but should instead provide the means to remedy them.

Designing a user interface that incorporates all of these characteristics is tricky because working on one characteristic often affects others. The more interface elements you add, the more stuff your users will have to process. Of course, the converse is also true: not providing enough help and support may make certain functions ambiguous. Creating something that is simple and elegant and at the same time clear and consistent is the difficult goal of a user interface designer.