UI terminology & soft and hard metrics
Perceptual Analysis
Structure – The location of design features or tools, such as menus, buttons or widgets as it relates to the users
Identifiability – How easily can the user recognize an icon or interface widget?
Widget/icon consistency – Does the interface use the same or similar widgets or icons for similar tasks?
Visibility, legibility and language – How easy is it for the user to visually process the current task? Does an icon accurately invoke an image response for the user, (ie will a user associate an icon with the correct command)? Is the language universally understood? How do color, contrast and size affect the legibility of the words or icons?
Visual and Auditory Feedback – Does performing a task result in efficient user feedback? ie opens a dialog, beeps, invokes a drop down menu
Scan paths and search patterns – If a user is looking for an unknown command or object, does the interface present an intuitive eye scan path for the user to visually search for the desired command?
Cognitive Analysis
Hick’s Law – The time it takes for a user to make a decision as a function of all possible choices. How efficiently can the user reach the desired task/outcome given the current interface options?
Consistency – Does this task/process perform similarly to other features?
Working Memory Burden – How much does the user have to remember during the current task? Short term memory and channel capacity for the human brain is limited to 7+-2 items. A user may only remember the 7 previous menu items or will only be able to think about 7 tasks in parallel. Actual channel capacity depends on the type of process involved.
Long-term Memory Burden – How much does the user have to remember from previous user experiences? Low long-term memory burden results in higher efficiency, only if the interface is intuitive.
Efficiency – How quickly can an experienced user perform a known task?
Intuitivism – How intuitive is the design such that an experienced user can re-learn a process quickly?
Learnability – How intuitive is the design such that a new user could understand how to perform a given task?
Error prevention – Does the interface have a means to prevent cognitive error in choosing options? Does this method reduce user functionality?
Error recovery – Does the interface have a means for the user to correct errors?
Motor-function Analysis
Cursor Travel Time ie Fitt’s Law – the time required for a cursor to rapidly move to a target area, as a function of the distance to the target and the size of the target.
Steering ie Accot-Zhai Steering law – The time it takes to navigate through a 2-dimensional plane without leaving a specified domain. For example, some hierarchical drop-down menus require the user to stay within the domain of the menu or the menu closes; this law estimates the time it takes to navigate to a second level or higher level menu option. The relevancy of the steering law is questionable, but the underlying principle, the difficulty in navigating hierarchical menus, is relevant.
Interaction type efficiency – How efficient is the given interaction type? Interaction types could be: point and click, point-drag, single click, multi-click, right click, middle click, scroll wheel, on-mouse-over, hot-keys/shortcuts, Tab-key navigation, Alt-letter(s), and/or arrow key navigation. For example, scrolling could be performed by mouse wheel, or by point-drag; short distance scrolling is most efficient using the mouse wheel while point-drag is most efficient for long distance scrolling.
