The conceptual model is the most fundamental aspect of the interface, describing the relationship between the interface and the outside world. The purpose of the conceptual model is to draw on the user’s past experiences so they can readily understand basic operations and accurately predict functionality.
The task flow is concerned with the manner in which users’ complete specific operations with the system. In contrast to the conceptual model, the task flow is largely dependent on the product’s technical environment.
The organizational model describes how the system’s content and functionality are ordered and categorized. Also known as the information architecture, the organizational model encompasses both the classification scheme as well as the model of association, hierarchy versus index for example.
The Viewing and Navigation layer encompasses the wide variety of behaviors and operations that allow users to navigate the interface and effect its presentation.
The Editing and Manipulation layer contains the behaviors that result in permanent changes to user’s stored information. … Behaviors in this layer can often be recognized by the following traits: they result in permanent, stored changes; they require an implicit or explicit save operation; and they typically require validation of the input data.
Interface elements that inform users of the application’s activity and status, as well as elements dedicated to user education, are all contained in the User Assistance layer. This includes online help, error alerts, and status alerts.
The various design decisions governing the placement and ordering of onscreen elements are expressed in the Layout layer. In addition to providing an ordered visual flow, the Layout layer also supports the Behavior tier by arranging elements in a manner that helps communicate behavior, importance, and usage.
Like many forms of visual design, the Style layer is concerned with emotion, tone, and visual vocabulary. Because it is the most visible and concrete aspect of an interface, it typically accounts for people’s first impression of a product. Paradoxically however, the ultimate effect of style on overall usability or user satisfaction is minimal.
Contained within the Text layer are all the written, language-based elements of the interface. This includes the labels used to represent the organizational model, the names of the input and navigational controls contained in the Viewing and Navigation layer, and the alert messages and help text used by the User Assistance layer.
Didn't find what you were looking for?
Our Human Interface Guidelines are a work in progress and we need your help. If you found an area that was unclear or is not even covered in our HIG, tell us about it. You'll find everything you need on our mailing list: email@example.com or in our little tutorial.
Please add any guidelines questions or requests to the HIG Questions page.
Also see the KDE3 User Interface Guidelines and KDE User Interface Guidelines and the Season of Usability HIG & Design Patterns Workspace.