What is usability? Pills.
The usability of a website is defined in relation to effectiveness, efficiency and satisfaction.
by ISO 9241 usability of a site is called: 'The effectiveness, efficiency and satisfaction with which specified users can achieve certain objectives in certain environments of use'. See in http://www.iso.org/
This definition is of 1993 and refers to computer artifacts in general.
THE THREE INDEPENDENT VARIABLES referred to are:
environments
objectives
users
In reality the concept of usability was born in the 60s', in ergonomics, in relation to any human - machine interaction artifact. There usability in a product itself. The sense of usability and user can not be separated from the environment of use.
The dependent variables in the above definition are: effectiveness, efficiency and satisfaction.
Effectiveness: that the accuracy and completeness with which to achieve certain results, the goal.
efficiency in the use of a product indicates the resources spent to achieve this in relation to the accuracy and completeness of achieving the desired result.
Satisfaction indicates the comfort, freedom from discomfort and constraints, the acceptability of the system, the favorable disposition of users use of the product.
In Italy the great discovery of the issue is the usability of Web sites with the publication of the book by Jakob Nielsen 'Web Usability'. Nielsen before becoming usability guru had worked at Sun - U.S. computer company where he invented the Java language - up to 1998 as a Distinguished Engineer.
Then, close to the usability issues were already long been under study by Donald Norman, an engineer and psychologist, former vice president of Apple's advanced research, involved in the design of the Macintosh user interface. One of the concepts designed by Norman is to affordance: quality that an object with its very form suggests how it should use. Ergonomics and usability
involve a design process that has at its center you.
With the advent of the Web, the problem of usability has been moved from the domain of software to the sites. A usable website is a prerequisite for its quality. The web designer at every stage of design should therefore take these type of questions: What is a web site? Who will use it and what do you expect to find? The same questions also guide
drafting of the content. Usability experts and then interact with the site design at any stage of implementation.
STILL POINTS IN THE DESIGN:
• The usability is designed from the start, and kept under constant review in the process of planning and development.
• Designing usable systems is difficult and requires specific expertise and professionalism.
• Evaluation of usability of a system can not by the user. Therefore it is necessary to put the user at the center of the design process.
To achieve this it is also essential to know the user.
To design a good system, specifically, we need to know: •
its needs and expectations in relation to system;
• "basic mechanisms of" User: perceptual, motor, cognitive,
• its socio-cultural: language, education, occupation, experience,
• The specific use that will do.
... then we must try. Check
through usability testing. Users
sample using the system by performing typical tasks in a controlled environment, under observation by usability experts who collect data, analyze them and suggest improvements.
levels of "maturity" within the user-centered design can be successfully arranged like this:
• FIRST STAGE: The product works
• SECOND STAGE: The product provides the functions required
• Third Stage: The product is easy to learn and use
• Fourth stage: The product is invisible in use.
"There are no simple answers, only tradeoffs
"
Donald A. Norman
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