Experiencing your design

User Experience (UX)

In the context of interaction, the UX is a combination of perception, actions, aesthetics and events that are meaningful to the user and as a combination deliver an engagement and a flow between the user and the prodcut or system being used. It is a somewhat evasive concept that either is there or not, and that depends very much on the user.

A Range of Resources

There is the Interaction Design Foundation, in particular their encyclopedia entry on User Experience.


UX Properties

There are many ways to evaluate user experience, below are listed some properties that I believe are most relevant...




Effectiveness How well a task was performed and how easy it was to do so. It is about the accuracy and completeness with which the users achieve tasks.
Efficiency Interaction duration, bandwidth and intensity, time-on-task, resources and modalities required. It relates to the resources used and necessary to achieve accuracy and completeness in the performance of tasks by the users.
Affect Effects of the interaction on the user emotions, moods, motivation and attitude, it is also about comfort What is the subjective effect on the user
Learnability Extent to which the interaction can be learned and memorised. Is it easy to become acquainted with the installation
Intuitiveness How little cognitive effort is required to perform the interaction, and to adopt the right behaviour in the installation How much prior knowledge and experience can be relied upon
Discoverability How little cognitive and perception efforts are required to discover the interaction. Can the user find out the different features of the installation
Context The granularity of the user perception of what is happening, as well as the overall time, location, domain, user and application combination. How much of an alternate reality is rendered in the installation
Usability Bugs, defects and their effect on user confusion, error, delay and failure to perform a task. The severity, pervasiveness and number of usability issues
Usefulness How useful are the interaction and the task performed in relation to the user intents and motivations. The discrepancy between usability and usefulness needs to be highlighted here Can the user do what s/he wanted to? Does it make sense to him/her?
Comfort Is the user comfortable while performing an interaction task, how good is the ergonomics of the device/system. How little physical strain does the user experience during his/her visit