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4.0.Usability    4.1.Basic principles

4.1.Basic principles

The issue of accessibility is a major concern for the online Ecosystem. The following considerations must be incorporated in the development of each application or website.

4.0.Usability      4.1.Basic principles      4.1.1.What is usability?

4.1.1.What is usability?

Part 11 of Standard EN ISO 9241 "Ergonomics of human-system interaction" describes usability as follows:

"Usability is the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use."Depending on their context of use (such as the user, the task, the tool and the physical and social environment), this results in the following three main criteria or metrics for the user-friendliness of software:

  • Effectiveness in completing a task. The accuracy and completeness of the goals (i.e., was the problem solved?).
  • Efficiency in dealing with the system. The resources used to achieve these goals, time and materials (i.e., how fast was the task achieved with the system?).
  • Satisfaction of users with the software. The subjective feeling regarding the interaction (i.e., acceptance by the user of the solutions offered by the system?).

4.0.Usability      4.1.Basic principles      4.1.2.How does a style guide provide support in this regard?

4.1.2.How does a style guide provide support in this regard?

A style guide and adherence to it can make a significant contribution to the achievement of the three main criteria of user-friendliness, in terms of both developers and end users:

  • Effectiveness
    Improved quality: The time needed to design user interfaces is reduced because basic guidelines are clearly documented, tools shared and best practice guidelines are available for other decisions.
  • Efficiency
    Improved process: A user interface will "collaborate" better as a whole because common and consistent design guidelines are available. Development of the initial prototypes is more effective because less reworking is required to solve usability problems.
  • Satisfaction
    Improved usability: Usability is improved, for both developers and users. It will be easier for developers to produce consistent and appealing interfaces, while users will benefit from increased ease of use.

4.0.Usability      4.1.Basic principles      4.1.3.Checklist: Principles of dialog design

4.1.3.Checklist: Principles of dialog design

Although the following seven Dialogue principles were defined in 1999, they are still valid today.

  • Task suitability
    The dialog helps the user to do his/her task effectively and efficiently.
  • Self-descriptiveness
    Each dialog step is immediately comprehensible through feedback from the application or the user is explained on request.
  • Controllability
    The user is able to start the dialog flow and to influence its direction and speed until the goal is reached.
  • Conformity with expectations
    The dialogue is consistent and corresponds to the user's characteristics, for example, the knowledge gained from the user's work area, training and experience as well as the generally accepted conventions.
  • Fault tolerance
    The user can achieve the intended work results despite clearly faulty input with either no or minimal corrections. Despite the faulty input, the application allows the user to achieve the intended objective with minimal corrections. Fault tolerance in usability is a seamless continuation of the principle fault tolerance in accessibility.
  • Customizability
    The application allows adjustments based on the requirements of the task, individual user preferences and user skills.
  • Suitability for learning
    Dialog helps the user to learn the system and provides guidance.

4.0.Usability      4.1.Basic principles      4.1.4.What makes a system user friendly?

4.1.4.What makes a system user friendly?

A system is user friendly if, among other things:

  • Functions can be recognized easily.
  • It is clear which action can be performed.
  • The action that was just performed can be identified.
  • It is easy to determine if the system has the desired status.
  • Error messages are clear and solution-oriented.