The user-friendliness (usability) of an application is regarded today as a decisive quality feature and contributes in the long term to the broad acceptance of a system.
Any modern user interface (UI) should comply with a set of rules that help to ensure user-friendliness (usability). According to DIN ISO 9241-11 usability is a quality concept that encompasses the following aspects of human-computer interaction:
- Effectiveness: The effective attribute addresses the accuracy and completeness with which a user reaches his or her goal and is supported by the system.
- Efficiency: The term efficient designates the resource expenditure used in relation to the accuracy and completeness of the work. For the system, the effectiveness determines the quality level of the system-based work support; the efficiency on the other hand, with which learning effort or with what average time expenditure a work task is mastered.
- Satisfaction: The satisfactory attribute finally characterizes the (positive) attitude and the emotional experience (joy of use) of a user.
User ExperienceWhat is User Experience?
Description of UX process
UX (user experience) extends the concept of usability to include aesthetic and emotional factors such as an appealing, "desirable" design, aspects of building trust or joy of use.
According to DIN ISO 9241-210 it includes all effects that the use of a user interface has on a user before, during and after use.
Part 110 of DIN EN ISO 9241 describes the following principles for the design and evaluation of an interface between user and system (dialog design):
- Task suitability
The dialog helps the user to do his/her task effectively and efficiently.
Each dialog step is immediately comprehensible through feedback from the application or the user is explained on request.
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 dialog 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.
The application allows adjustments based on the requirements of the task, individual user preferences and user skills.
- Suitability for learning
The dialog helps the user to learn the system and provides guidance.
Related Methods & Tools
ISONORM - A tool that shows how users rate a product along the design principles as defined by ISO 9241/110.TU Berlin - Questionaire
This information was written in collaboration with the UX Guide. Daimler UX Guide (internal link – requires authentication)