Interface Usability - the Principles

Interface usability is a very important factor for both a standalone application and a dynamic website. If the application provides useful and sophisticated functionality, but the users can't figure out how to use it, this application will never be popular.

Among the basic usability principles, the following are most often cited by usability experts: simplicity, consistency, understandable language, accessibility and good means of control of the current status.  

Simplicity means that every potential user of the application should be able to quickly and intuitively guess how to fulfill one of another task. Of course, different audiences require different levels of simplicity.

Since every person has a different idea of what is simple, and for the developer of the application it's always intuitive, it's always advisable to run an application through usability testing and to invite testers that represent the application's target audience . For example, if the software is written for children of 8 to 12 years of age, the testers should be kids of the same age.

Consistency refers to the sameness of the navigation means/interface elements throughout the application/website. It's already difficult enough for new users to learn your interface once; there is no need to make them re-learn it every time they move from page to page or from screen to screen. It's also a good idea to comply with existing standards and make your application reasonably similar to other applications in the same class. Your users will appreciate it if you use the same shortcuts as everyone else.

The language issue brings up an important consideration. First of all, your messages should be brief and clear, just so the user can easily guess the meaning of menu items, buttons and other interface elements. There is no need to be cryptic or try and sound sophisticated. Save your users' time; speak to them in plain language without unnecessary technical jargon.

Accessibility is another way (along with multilingual support) that can help you expand your potential audience. Make sure that people with disabilities will find it as easy as possible to use your application or website and you will be rewarded for your effort with more sales and happy customers.

Last but not least, help your users to always be aware of where they are. If you are developing a standalone application, make sure you provide a clear indication of the status of work the user is doing, which tasks have been completed successfully or failed and what else has to be done. If you are building a website, show the user which section of the site he/she is currently exploring and how to get back the easiest way possible. It's very important to avoid confusing navigation patterns.  

Remember that all efforts you put in the usability of your standalone or web-based application will quickly pay for themselves.