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Usability and usable web sites
What are the key issues of Usability?
Jenny Preece, Professor of Information Systems at South Bank University, London wrote in Human-Computer Interaction 1994 that "Usability, a key concept in Human Computer Interaction, is concerned with making systems easy to learn and easy to use". Over the centuries a lot of work has gone into design of books and the graphic arts but only comparatively recently has much thought gone into the human aspects of design of computers and computer systems. It has been found that many systems fail because of bad design and usability and the phrase 'a user-friendly system' has become a description used as a sales ploy rather than a reality.
People use and operate technology in a variety of different ways, for a variety of different uses. There are several different factors that combine to make a well designed, useable system which is what HCI specialists try to understand. Among these factors are psychological, ergonomic, organisational and social factors which contribute to system usage for better or worse but that putting people first in design has improved the systems and so their effectiveness and productivity.
A great deal of research has been carried out into cognition, which looks at the process of how humans acquire knowledge, how thought processes work and how things are remembered. Experiments carried out by Klemmer and Frick in 1953 showed that to fill an interface screen with information is of no value to a user as only a limited amount of this information will be used, remembered and understood by a user. Memory retention is assisted by including context and associations. It is easier to remember when presented in a format which promotes a particular operations context and gives the user a model in their mind.
In Design Goals, Tony Hoeber points out the merits of good design. Good visual design is made up of how each element looks and how they work together. Designers should strive for simplicity for anyone using a new task, consistency with similar applications and efficiency so that the task itself can be carried out efficiently. Piagetts work on the theory of developmental cognition links to these design goals. The stages of development which are basically doing, visualising and understanding, should be present in a screen display at the same time to make the user more able to follow the information or choices he has.