Big ideas.
Plain English.

Comparing randomly assigned versions of an experience to estimate how a specific change affects a defined outcome.

Making an experience usable by people with disabilities, including people using assistive technology or alternative ways to interact.

Grouping observations by shared meaning to find patterns, while keeping a link back to the evidence behind each group.

An action made possible by the relationship between a person and an object. A cue that communicates the action is a signifier.

A text alternative that conveys an image’s purpose in its context. Purely decorative images normally use an empty alternative.

HTML attributes that communicate roles, states and relationships to assistive technology when native HTML cannot express them adequately.

A sequence of links showing where a page sits in a hierarchy, with a route back to its parent sections.

A research activity in which participants group labeled items, helping a team understand possible ways to organize information.

The mental effort a task places on someone. Unfamiliar labels, hidden context and competing information can add avoidable work.

A tendency to favor information that supports an existing belief, for example noticing positive feedback while overlooking contradictory observations.

Planning and shaping information so people can understand a situation and complete a task, across words, structure and format.

Learning about a task by observing and discussing it where it actually happens, including the tools and interruptions around it.

The proportion of a defined population that completes a chosen action within a specified period. Its meaning depends on that denominator.

Shared principles, reusable interface patterns and guidance that help teams create and maintain a coherent product experience.

A named design decision, such as a text color or spacing value, stored so it can be reused consistently across tools and code.

How readily someone can find an available feature or action when they need it, without already knowing where to look.

The interface shown when a view has no content. It should explain the situation and offer an appropriate next step if one exists.

Designing a flow to reduce foreseeable mistakes before they happen, through constraints, clear instructions and review opportunities.

Information that makes the result or current status of an action perceptible, such as a saved message or a processing indicator.

The sequence in which controls receive keyboard focus. It should preserve meaning and make the task possible without a pointer.

Research used while a design is taking shape to understand needs, uncover problems and guide the next iteration.

A structured expert review against usability principles. It can reveal likely problems but does not replace observing users.

The organization, labeling and relationships of information that help people understand where they are and find what they need.

The physical and mental effort needed to complete an action, including reading, remembering, deciding and operating controls.

A representation of a person’s experience over time, connecting goals, actions and difficulties across relevant touchpoints.

A situation where keyboard focus enters a component but cannot leave through an expected keyboard action.

How easily people become able to use an interface, particularly when they first encounter it or return after time away.

A person’s working understanding of how something behaves. It may differ from the way the underlying system actually works.

Short interface text that helps someone act or interpret a result, such as button labels, field hints and error messages.

A usability session facilitated by a researcher who introduces tasks, observes behavior and asks neutral follow-up questions.

The mechanisms that let people move through an information space and understand which destinations are available.

Support that helps a new user reach an initial useful outcome, from setup to learning the actions needed for their goal.

An evidence-based representation of a relevant user pattern, centered on goals and behavior rather than invented demographic detail.

Presenting detail when it becomes relevant so the initial view stays manageable, while keeping additional options findable.

A representation used to explore or test an idea. Its level of detail should match the question being investigated.

Research that examines experiences, behavior and meaning in depth to explain how or why something happens.

Research that uses numerical observations to estimate quantities, compare groups or test defined hypotheses.

Identifying information when it is presented, instead of retrieving it unaided from memory. Visible choices can support recognition.

An approach that lets layout and content adapt to the available space while preserving usability across screen sizes and zoom levels.

Assistive software that conveys interface content and structure through speech or braille and provides commands for navigating it.

A perceivable cue that communicates where or how to act, such as an underlined link or a clearly labeled handle.

Whether a participant achieves a predefined task outcome. A study should specify what counts as success and whether help is allowed.

Evaluating an information hierarchy by asking people to find a destination in a text-based structure without visual layout cues.

How effectively, efficiently and satisfactorily specified people can achieve their goals with a product in a particular context.

Observing representative people attempt realistic tasks to understand where an interface supports or obstructs them.

A sequence of actions and decisions through which someone can reach an outcome, including branches and recovery paths.

The arrangement of size, position, spacing and emphasis that communicates relationships and guides attention through a page.

A simplified layout used to explore content, structure and interactions before committing to detailed visual styling.