Museo&Web
Planning Kit for a Quality Site for Small and Medium Sized Museums
Principles of Usability
From the Handbook for quality in cultural Web sites Improving quality for citizens, paragraph 2.3.2:
It is not always possible to plan and realise a Web site using the methods described above directly. This is because the organisational, financial and human resources (sample users, experts on usability etc.), required are not always available.
From experience using this methodology, experts in usability have proposed a series of Principles and Criteria that can guide decision making in planning in order to reach effectiveness, efficiency and satisfaction in the realisation of a Web site.
The principles of Usability tend to group problems in general categories. The most common principles are the following:
Visibility: give users visual clues to understand how to use the site. for example: a word or phrase underlined in blue indicate the presence of a link, underlining in purple indicates that the link-site has already been visited.
Affordance: ensure that objects behave in a manner that their appearance suggests. In order to complete the function assigned to them a button should require to be pushed and not, for example, to be highlighted.
Natural Mapping: establish conceptual correspondence between command and function. For example, for the layout of a form in a search function, the text should be typed into the input field and the “Return” button should be pressed.
Constraints: reduce the number of ways in which a certain action can be carried out and plan the commands for functions in a way that renders their use easily understandable.
Conceptual Models: the user has a notion of how things work, based on his/her experience and knowledge. A good conceptual model in a Web site is one where the proposed functions correspond as far as possible with the user’s notion of those functions.
Feedback: indicate the users’ position in the operation or task, his/her result, be it positive or negative. For example, when the user downloads a file, indicate time required and time remaining for the operation. When the user sends a form, confirm receipt.
Safety: as far as possible limit the risk of error on the part of the user. In the case of error, give information as to possible causes and remedies.
Flexibility: give users the possibility to execute an
operation in various ways. For example through various navigational
routes to reach a document.