Glossary
Searchable terminology from accessibility, web standards, and related fields.
30 results found in Usability.
- Above the Fold (Above-the-fold, First Screen Content)
- Content that is visible on a web page without requiring the user to scroll. The term originates from newspaper publishing where important headlines appeared above the physical fold of the paper. In di…
- Accessibility Heuristics (Accessibility Heuristic Evaluation)
- A set of broad usability and accessibility principles used to evaluate digital products for barriers that may prevent people with disabilities from using them effectively. Unlike detailed technical ch…
- Caption Flow (Captioning Flow, Text Flow)
- The smoothness and regularity with which caption text appears and updates on screen during real-time captioning. Good caption flow means text arrives at a consistent pace without jarring delays, sudde…
- CogTool
- A cognitive modeling tool developed at Carnegie Mellon University that generates quantitative predictions of human task performance times based on the Keystroke-Level Model (KLM) and the ACT-R cogniti…
- Cognitive Usability
- The extent to which a system, interface, or information resource can be effectively used by people with varying cognitive abilities and processing styles. Cognitive usability goes beyond traditional u…
- Discoverability (Feature Discoverability)
- The degree to which a user can find and become aware of a feature, setting, or capability within a system. In accessibility, discoverability is a critical challenge because users who could benefit fro…
- HHS Usability Guidelines (Research-Based Web Design and Usability Guidelines, Usability.gov Guidelines)
- A comprehensive set of evidence-based web design and usability guidelines published by the U.S. Department of Health and Human Services (HHS). The guidelines cover areas including homepage design, pag…
- Heuristic Walkthrough (Heuristic walk-through)
- A usability evaluation method proposed by Andrew Sears (1997) that combines scenario-based cognitive walkthrough with heuristic evaluation. Evaluators work through realistic user tasks using a priorit…
- Human Factors Engineering (Ergonomics, Human Factors)
- The scientific discipline concerned with designing systems, products, and environments to be compatible with the physical and cognitive capabilities and limitations of the people who use them. In acce…
- ISO 9241-210 (Human-Centred Design Standard, Ergonomics of Human-System Interaction — Part 210)
- An international standard specifying the principles and activities of human-centred design (HCD) for interactive systems. It defines a six-step iterative process — understanding context of use, specif…
- Jakob's Law (Jakobs Law, Law of Familiarity)
- A usability heuristic coined by Jakob Nielsen stating that users spend most of their time on other sites and expect your site to work like the ones they already know. Accessibility implication: novel …
- Keystrokes Per Character (KSPC)
- A metric used to evaluate the efficiency of text-entry methods by measuring the average number of keystrokes required to produce each character of text. A lower KSPC indicates a more efficient input m…
- Latency (Delay, Lag, Response Time)
- The time delay between when an event occurs and when its accessible representation is delivered to the user. In real-time captioning, latency is the gap between spoken words and their appearance as te…
- Mental Workload (Cognitive Load, Cognitive Workload)
- The amount of cognitive effort and mental resources required to complete a task. In accessibility contexts, mental workload is an important measure of how demanding an interface is to use — an interfa…
- Menu Selection (Menu Navigation, Menu Selection Task)
- A fundamental computer interaction task in which a user chooses an option from a set of items presented in a menu structure, typically involving locating the target item, moving the cursor to it, and …
- Multi-Layered Interface (ML Interface, Layered Interface, Training Wheels Interface)
- An interface design approach where novice users start with a reduced-functionality layer containing only basic features, then progress to more complex layers as they become comfortable. This technique…
- Navigability (Ease of Navigation, Web Navigability)
- The ease and efficiency with which a user can move through a web page, application, or document to reach their intended content. For accessibility practice, navigability is a primary determinant of wh…
- Novelty Effect (Novelty bias)
- A research-methodology concept describing the tendency for users to behave differently with a new technology simply because it is new, rather than because of its enduring value. Novelty effects inflat…
- Overshoot (Cursor Overshoot, Target Overshoot)
- In pointing device interaction, the phenomenon where the cursor travels beyond the intended target before the user can stop it, requiring corrective movements back toward the target. Overshoot is meas…
- Psychometric Evaluation (Psychometric Validation, Psychometric Analysis)
- The process of assessing whether a measurement instrument (such as a questionnaire or survey) possesses desirable statistical properties including validity, reliability, and consistency. In accessibil…