Web Site Usability - What is it?

The primary thing that makes a web site usable is how well it enables someone to achieve what they want to do. To achieve this goal a web designer needs two things. First, you need to understand the basic principles of usability. Secondly, you need to understand the users of the web site and design the site with them in mind.

The International Organization for Standards (ISO) has a definition for usability:

...the effectiveness, efficiency and satisfaction with which a specified set of users can achieve a specified set of tasks in a particular environment (ISO Standard 9241).

However, everyone has their own definition of usability, "If I cannot use it, it is not user friendly."

Usability expert, Jakob Nielson lists ten general principles for user interface design.

1. Visibility of system status - Always keep the user informed about what is going on.

2. Match between system and the real world - The system should speak the users' language.

3. User control and freedom - Support undo and redo.

4. Consistency and standards - Users should not have to wonder if different words or actions mean the same thing.

5. Error prevention - Eliminate error prone conditions

6. Recognition rather than recall - There should be no need to remember information.

7. Flexibility and efficiency of use - Allow users to tailor frequent actions.

8. Aesthetic and minimalist design - Extra information competes with relevant units of information.

9. Easy error recovery - Error messages should be in plain language.

10. Help and documentation - Easy to search.

You may be eager to jump right into the designing of your web site. You are excited about your ideas. While your ideas may be very good, you need to stop and take time to get feedback from others.

Before you can consider design solutions you need to have a solid understanding of the problems you are trying to solve, the business requirements, and the user needs. If you do not have this information you should not be considering design solutions.

Depending upon the purpose of the web site these initial steps can be determined very quickly or they may require significant input from business associates and end users. Extensive task analysis and scenarios may be needed. Personas can be developed to help facilitate this process.

It may be helpful to involve end users in the research phase of the design, depending upon the purpose of the web site. It is much better to have their involvement at the early stages as it will save you heartache later.

As the web site is designed, it is important to have usability reviews. As a designer, you must not think of these reviews as critiques of your design. The objective of the usability review is to make the web site design even better. Your budge may determine the extent of the usability review. But even with a minimal budget, a review by a few end users will be very helpful.

After your web site is online and live you still need to keep working on usability. Small improvements in the web site usability can result in significant increases in your desired results from the web site. If your desired results are measurable, you need to test if changes on the web site can improve performance.