As organizations grow increasingly dependent on computer application systems, the ability of the end-user of these systems to use them effectively becomes critical, in some cases to successful functioning of the whole organization. If end-users find that the system actually interfaces with, rather than enhances, their work, and if it causes them undue stress and frustration, then they may find it inefficient to use, and may actually cease to use it altogether.

The programmable, or software, interface, which allows interaction between end-users and the computer, plays a vital role in the effectiveness with which a human-computer system functions. The user interface generally consists of information displayed to the user and facilities, which allow the user to enter information into the computer, to manipulate information, which is displayed, and to take control actions. It enables the end-user to access and make use of the facilities and functions, which the system provides, and to carry out the tasks for which it has been designed. It provides the user with information about the system, about what it does, and about what the user can and should do. It enables the user to learn about the system and to build an understanding of how it works.

If this interface is poorly designed, it can severely restrict the user's ability to use the system. It can cause confusion and frustration, difficulty in learning how to use the system, misunderstanding of what the system is doing and of what the user should do, errors, and difficulty in using the system to carry out tasks successfully.

It is therefore essential that the user interface meet the needs of those using the system to carry out tasks. A large, and increasing, body of research, recognizing the need for 'User-Centered' Designed, is currently investigating how the user interface should be designed in order to meet these needs. This area of research is generally known as 'software ergonomics' or 'cognitive ergonomics', and falls within the discipline of 'ergonomics' or 'human factors'