Glossary » s

SAFE

simplicity, appropriate form, function (workability & beauty), economy of effort. SAFE design principles were the organizing principle of the modern design book “art: an approach”, by Robert C. Niece, 1959.

safety

minimizing the risk of harm to people or the environment. Possible types of harm include physical harm (repetitive stress syndrome, electrocution), mental anguish (lack of privacy, negative self-attributions), and threats to property (fraud, vandalism).

Safe systems attempt to minimize both…

safety-critical system

any system whose reliable performance is important for ensuring the health and safety of users and the public, including for instance, power plants, clinical systems, emergency response systems (police, fire), hazardous chemicals systems, and many military systems.

satisfaction

a common reference to the set of subjective responses a person has when using a system. Typically satisfaction is measured with questions that have their responses on Likert scales, e.g. “How satisfied are you with this software? (1=very dissatisfied, 7=very…

satisficing

a theory of human reasoning that says that people minimize cognitive load by minimizing reasoning and using quick heuristics to make decisions. Thus, people avoid complex memory, planning, and decision-making in favor of acting upon information immediately available perceptually, well-known…

scaffolding

a teaching technique where support tools help manage mechanics that would be difficult to master while the students learns higher-level concepts.

scanning

for the physically disabled, the ability to move through a set of options (usually automatically) and to select one of the options. This enables an interface with only one input: “select now”. With this interface, a user can select objects…

sccs

source code control system or version control system (vcs) or revision control system (rcs); a software application designed to help coordinate document modifications and updates among a group of people (especially coordinating updates to software source code). Source code control…

scenario

a design envisionment technique whereby a set of representative target users are identified and an outline is created of their lives, their goals, their interests, their schedules, and their interaction with the system being designed. While these descriptions of different…

schedule chart

a diagram used in project management, planning, and scheduling. The schedule chart shows the different resources and activities involved in a project and time dependencies between them. With this diagram, a critical path can be found that indicates the shortest…

scientific visualization

the graphical representation of complex physical phenomena in order to assist scientific investigation and to make inferences that aren’t apparent in numerical form. Typical examples include processing of satellite photographs and 3D representations of molecules and fluids to examine their…

scope notes

text associated with a link, such as a brief description or keywords, that helps a user determine the scope of the content that is accessed through that link. Other scope information might include representative sublinks, or a number indicating how…

scoped search

a search that applies to only a subset of the entire database, in order to narrow down results and get a more exact match. Scoped search should be avoided because users will often choose the wrong scope and get a…

screen font

a font designed for legibility when displayed on a computer screen (or, for example, on a television screen) as opposed to a “printer font”, which is optimized for printing. Screen fonts need to be designed for clarity on the relatively…

screen inertia

the principle that as a user moves from screen to screen or web page to web page, there should be such consistency that the only things that change represent new information.

In contrast to this approach, there are certainly times…

screen pop

a feature in telephone-based customer service applications that brings up a customer record automatically on the screen of the customer service representative when they receive a call.

screen reader

a program that reads out a computer display for the visually-impaired or for those who do not have access to a monitor. The screen reader can read text that appears in a standard way in dialog boxes, menus, icons, and…

screen real estate

the amount of space available on a display for an application to provide output. Typically, the effective use of screen real estate is one of the most difficult design challenges because of the desire to have as much data and…

screen refresh rate

the frequency at which a monitor can update its display; in CRTs, the rate at which the electron beam repeats its pass over the entire screen to refresh the dimming phosphors. The refresh rate represents the maximum rate at which…

screen scaping

converting a character-based user interface to a graphical user interface by capturing the output of a character-based system and doing a surface-level transformation into the GUI. This is a simpler approach to upgrading a legacy system than reimplementing it, but…

screen-enlargement utility

a system for zooming in on portions of the screen to make it easier for the visually-impaired to view information on computer monitors. Also called a screen magnifier.

screenshot

or screendump / screen snapshot / screen capture; a picture of a screen capturing the appearance of the user interface at a given point of time, typically a printout, but also including electronic snapshots.

Screenshots can be used for focus…

script

(multimedia) a specification used to generate a multimedia presentation. The script contains all the details of each shot and scene, usually along with a storyboard. The script contains drafts of all text, graphics, and other media and their timing, interaction,…

scroll arrow

a small arrow at either end of a scrollbar that can be clicked to shift the view area of a document incrementally in one direction at a time.

scroll elevator

a box within a scrollbar that allows the user to move to a specific region by dragging the box to the appropriate location within the scrollbar. Also called a “scrollbox” or “thumb”.

An elevator is somewhat unique in the Open…

scroll thumb

a box or “thumb” within a scrollbar that allows the user to move to a specific region by dragging the box to the appropriate location within the scrollbar. Also called a “scrollbox” or “elevator”.

scrollbar

(or scroll bar) a control for moving the view of an area that is too large to be entirely visible in its display region. Vertical scrollbars (shown below) move the data up and down, and horizontal scrollbars move the data…

scrollbar gutter

or scrollbar channel; the area of the scrollbar that is outside of the scrollbox. Clicking within the gutter pages up or down.

scrollbox

a box within a scrollbar that allows the user to move to a specific region by dragging the box to the appropriate location within the scrollbar. Also called a “thumb” or “elevator”.

scrolling listbox

a list of text items that can be scrolled, usually allowing one or more items to be selected.

search

the mechanism that enables users to find things in large information spaces. Search issues fall into 3 common categories: how people specify their search queries, what determines a “relevant” match, and how search results are displayed.

…

search engine

a tool that allows a person to enter a word or phrase and then lists web pages or items in a database that contain that phrase. The success of such a search depends on a variety of factors including: the…

Section 508

a set of guidelines for accessibility of information technology for the U.S. federal government. Section 508 requires that all federal government IT development or purchases be accessible, following the 508 guidelines, or be the most accessible among the options.

(Section…

see-and-point interface

a user interface that displays objects and options, and a user only has to point to (and click on) the relevant object to issues commands and perform tasks. See-and-point interfaces are in contrast to remember-and-type interfaces that do not have…

seizure disorder

in some types of epilepsy, a seizure can result from the presentation of a rapidly-varying stimulus, such as flashing lights and repetitive sounds. Thus, interfaces should avoid strobe effects, blinking effects, and repetitive noises. In most interfaces, these are likely…

select-then-operate paradigm

an approach to direct manipulation user interfaces where a user must first select an object (icon, piece of text) and then choose an action to perform on that object (copy, make it boldface, print). This is the typical approach used…

selection

an object, set of objects, or region that the user has recently chosen. The user can then act on the selection, e.g. by cutting and pasting it or selecting menu items that set attributes of the selection. Examples of selections…

selection bias

in choosing test users for a usability study, selection bias is any imperfection in the selection process that gets either the wrong types of users (people who aren’t in your target audience) or a sample of users that is not…

selection box

a box, also known as a marquee, that appears around a selected region, such as a rectangular area selected in a drawing program.

selection pointer

a pointer in the shape of an arrow, used to select and drag icons and other graphical objects.

self-report

any method of gathering usability data through having the user report what happened. This may be by having users record themselves on tape or writing down in diaries. They may range from open-ended reflections to very specific questionnaires that users…

semantic differential

a type of survey question where respondents are asked to rate their opinion on a linear scale between 2 endpoints, typically with 7 levels. For example:

Please rate this software on the following dimensions:

easy to use 1 2 3

…

semantic directness

the degree of translation required from a user’s conceived goal to the action needed to achieve the goal, based on how that action is supported by system features.

semantic net analysis

a method for understanding the structure of a domain by diagramming the relationships between objects in the domain and attributes of those objects. The information for creating a semantic net is usually obtained by interviewing users and domain experts. The…

semiotics

the study of signs and symbols and their use in communicating meaning, especially useful in analyzing the use of icons in software, but also appropriate to the analysis of how screen design as a whole communicates, and to how users…

sense of presence

the degree to which people feel that they are co-located with the others they are interacting with despite the fact that they are communicating over a distance using technology. The sense of presence might be enhanced, for instance, by: more…

sensory defensiveness

and tactile defensiveness; an adverse reaction that some users may have to touching devices with certain temperatures, textures, or materials, which may be due to allergies, physical sensitivities, or psychological aversion.

sensory modality

A communication channel associated with one of the human senses of sound, vision, touch, smell or taste. As used in discussing usability this may imply input to and output from the computer as well as the human user. E.g., the…

separable user interface

a user interface implementation that allows the user interface to be modified without modifying the backend code, and vice versa.

separator bar

a heavy line dividing items in a list, with possibly an item title and item controls (NewtonOS term).

serialization

the process of strictly ordering events. When two users perform actions that are dependent on each other, it is crucial to decide in what order those actions occurred and to impose the same ordering in the view of each user.…

session

an interactive connection involving more than one person and including all of the objects that they are sharing.

For instance, a videoconferencing session could be set up between two people which included a video connection and a shared whiteboard (a…

session control

the mechanism for mediating which people and which objects can belong to a given interactive session.

Important issues are the means by which users enter and leave a session, how a session is started and ended, and what resources are…

shared whiteboard

allows two or more people to view and draw on a shared drawing surface even when they’re at a distance. This may be used, for instance, during a phone call, where each person can jot down notes (e.g. a name,…

shared window system

a system that allows a single-user application to be shared among multiple users without modifying the original application. Such a system shows identical views of the application to the users and combines the input from the users or allows only…

shopping cart

a common metaphor used in web-based ordering systems. Users search for products, then add them to an abstract shopping cart. The entire list of items in the shopping cart is listed when they go to an order page to finalize…

shortcuts

any means of providing a faster method to accomplish a task than the general-purpose method, such as assuming typical default values. Shortcuts can be provided for experts that novices might have difficulty using, such as inconsistent methods for common tasks,…

side effects

actions that occur as the result of a user action which do not seem to the user to be related to the primary goal of the action. For instance, when starting a game changes system configurations (such as screen and…

side-channel messaging

in multi-person conversations (such as meetings), side-channel communication is communication between a subset of those in the conversation that is done without disrupting the primary conversation. For instance, in a videoconference, side-channel messaging systems allow a person to send a…

SIGCHI

special interest group on computer-human interaction. A professional organization that operates as part of the ACM (association of computing machinery) that brings together academics, students, and practitioners to study HCI (human-computer interaction). SIGCHI sponsors the annual CHI conference.

similarity matching

a technique for identify conceptual categories. Users are given a set of topics, and they are asked to rate the similarity of pairs of topics (on some scale, e.g. 1 to 10). These ratings can them be combined with a…

simplicity

the principle that user interfaces should be “simple” for users. Simplicity is used loosely to refer to the need to minimize the number of steps involved in a process, to use symbols and terminology that make the interface as obvious…

simulator sickness

virtual environment sickness or cybersickness; an adverse reaction to immersion in a 3D virtual environment characterized by symptoms of nausea, motion sickness, disorientation, and loss of control over movement. This reaction is typically explained by sensory conflict theory, the idea…

single-case experimental design

a method for determining the effect of an experimental manipulation with only one test subject (one user, one organization, etc.), basically by applying and removing the intervention over time:

measure the dependent variable initially apply the intervention, and measure

…

single-display groupware

SDG; a system where 2 or more people can simultaneously interact with a computer displaying on a single monitor. This is quite common for arcade games, but may be practical for certain educational applications and monitoring applications. The key problem…

site visit

going to target users’ workplace to see how they work, interact directly with them, conduct interviews, and see their work artifacts. Interaction can range from directly interviewing to inconspicuously observing. Visits can be brief or long-term.

sitemap

a representation of the organization of a website, usually including links to all the pages on the website. Used to help users find and get to pages on the site and help them build a conceptual understanding of the site…

situated action

the notion that people’s behavior is contextualized, i.e. the situation is a very important factor in determining what people will do. In the extreme view, this is the idea that you can’t generalize and predict people’s behavior from one situation…

situational impairment

a difficulty accessing computers due to the context or situation one is in, as opposed to a physical impairment. Examples include noise, poor lighting, distractions, other tasks that require use of hands or eyes, and social constraints such as the…

skins

alternative look and feel for the same application that can be swapped by the user, especially window styles and button styles, enabling highly personalized artistic styles in the user interface. Sometimes called chrome.

skip link

a link on a web page which, when clicked, skips down to a place lower on the page (i.e. a page link). The deliberate intention of a skip link is to enable a user to skip unimportant, uninteresting, or redundant…

slider

a control that lets a user drag a knob along a linear track to specify a value within a limited range. Often includes tick marks to indicate steps for the values. Also, if the range is not continuous, the slider…

slip

(psychology) an error resulting from skilled behavior being performed at a time when it shouldn’t, such as accidentally driving to the office when you intended to drive to the store. Highly-practiced behaviors become automatic and the triggers for these automatic…

slow in and slow out

in animation, the acceleration and deceleration of action, i.e. the way that an action begins slowly, moves quickly through the main action, and then slows down as it comes to a stop rather than moving linearly from one position to…

Slow Keys

a keyboard feature that prevents keystrokes from registering until a key has been held down for a certain period of time. This is extremely useful for people with motor impairments that make it difficult to target keys accurately or that…

small user interface design

SUI; design for extremely small output devices such as cell phone displays, watches, car radio displays, and other small information appliances.

Smalltalk

One of the earliest object-oriented programming languages, Smalltalk was unique in its tight integration with a graphical user interface. Smalltalk-80 is the best-known version, which has been a dramatically significant influence on every object-oriented system afterwards. Smalltalk is known for…

snapping / gravity

a graphics input technique – when people draw or drag objects near a gridline, guideline, or another object, the object they are drawing or moving automatically jumps into alignment (snaps) as soon as it gets close, as if the guideline…

snapshot

(groupware) a quick photo of another person that updates periodically to provide a basic awareness of their presence. (Also called a “porthole”.)

Snapshots are vaguely similar to a videoconference, except that no audio is provided, the frame rate is intentionally…

social psychology

the study of how people interact in groups, how they think about groups of people, and how other individuals affect a person’s behavior. Social psychology overlaps with other fields in their interest in communication, motivation, and social cognition.

Social psychology…

social responsibility

the notion that computing should be used to further the welfare of humankind, and that as designers, we ought to put strong focus on ethical issues such as safety, privacy, accessibility, respect for the users, human empowerment, achievement, and dignity.…

sociogram

a diagram that shows interaction patterns between people; for instance, a diagram with a node to represent each individual and lines drawn between individuals to indicate that they interact frequently. These diagrams can be used to study workflows, the clustering…

softkey

a key whose label is specified in software, as in ATM machines and mobile phone interfaces.

software crisis

the problem that software engineering techniques are not fully keeping pace with the demands being made on software, thus creating a situation where modern complex computer systems are extremely fragile: unreliable, insecure, and full of bugs. The problem has many…

software monitor

a piece of software that tracks user activity to understand the actual usage of an application or to keep track of actions during user testing. Typically, it records user events, such as keystrokes and mouse clicks, and may record higher-level…

spamdexing

efforts to fool search engines into providing a high relevance ranking for the pages of a website, even when the website may not be an appropriate match for a given keyword. This is undesirable because it interferes with users attempts…

speech act

a view of language that treats communication as a series of actions in the form of speech, where each action is intended to cause some change in the world outside the speaker, whether it be:

…

speech impairment

difficulty in spoken language, whether through vocalization or articulation impairments or through neurological language disorders. Computers can facilitate communication for people with speech difficulties. The field of study examining this is called AAC — Augmentative and Alternative Communication.

Aphasias (language…

speech-to-text system

a type of voice-recognition system – it converts spoken language to text. Useful for text entry and command entry, especially for people whose hands are busy with other tasks and for people with motor impairments.

speed

a metric for human performance. How quickly does a person react to a stimulus (reaction time)? How much time does it take for someone to perform a given task (task completion time)?

Also, a metric for system performance. How quickly…

speed-accuracy tradeoff

in many types of perceptual-motor tasks, there is a tradeoff between how fast a task can be performed and how many mistakes are made in performing the task. That is, a user can either perform the task very fast with…

spider

a program that downloads web pages and follows links to explore every web page it can find, usually with the goal of indexing every web page for a search engine, but also used to do other forms of research and…

spin box

a widget for input of numbers, consisting of a text entry field that allows only numbers to be entered and 2 small up and down arrows for increasing and decreasing the value.

spiral model

a classic approach to project management. The spiral model is an iterative approach that begins by developing basic requirements, building small simple prototypes, evaluating those prototypes, and then expanding into refined requirements and consecutively larger prototypes, until a complete deliverable…

splash page

or splash screen; a website homepage that is used for emotional impact and has very little navigation or information. Instead, it typically just displays a large and stunning graphic or a simple typographic message to intrigue the viewer and lure…

split bar

a short, thick black line at the end of a scrollbar that can be dragged to split a window into independently-scrollable panes. As it is dragged, a dotted line, called the split line, appears to indicate where the panes of…

split line

a line separating two panes of a split window. A split line can be dragged to the edge of a pane to eliminate the pane.

split window

a window that is divided by a split bar; a window with 2 or more panes which can be independently scrolled, but that all view the same underlying document. Splitting a window is useful if the user needs to view…

spoken language interface

a user interface where the user can, at a minimum, issue spoken commands, and optimally, conduct all interaction with the computer via speech. Speech systems are differentiated by:

…

spot graphic

an image used as an illustration or decoration on a page or on the screen, generally without a functional purpose other than its visual appeal and dynamics within a layout.

spring-loaded mode

also called a user-maintained mode or quasimode. A mode that must be actively maintained by the user, such as the use of the shift key on a keyboard, where other keys are only interpreted as capital letters while the shift…

sprite

an operating system capability that allows programmers to easily create independent graphical objects (“sprites”) that can move around the screen. A sprite automatically handles redrawing areas of the screen that it crosses over, saving the programmer from worrying about updating…

squash and stretch

in animation, elastic distortions of shapes during motion, especially of living creatures, to reflect the stretch of elastic body tissue, such as cheeks stretching and bulging during chewing. These distortions may be exaggerated to clarify an action, but the common…

squint test

evaluating a graphic layout by squinting your eyes. This tests legibility and whether the overall layout is a strong, clear layout.

staging

in animation, the choice of composition, viewpoint, and acting to communicate most effectively without confusion, distracting details, or tradeoffs that sacrifice clarity.

stakeholder

a person who is concerned with the outcome of a user interface design because of some effect it has on them, including users, clients, managers, software developers, designers, marketers, distributors, store-owners, and almost everyone involved with a product. Ideally, every…

standard

or “norm”; a rule for how user interfaces should be designed for given tasks, users, and contexts. User interface standards are usually encoded in style guides and are available for every major operating system. Standards help to ensure consistency across…

standards inspection

a design review to determine whether a user interface design conforms to standards, whether broad industry standards, corporate standards, or standards specifically designed for a given project (e.g. conformance to a style guide).

Standards may include such issues as screen…

starfield display

a refinement of a scatter diagram used in information visualization. A starfield display charts a large number of datapoints with individual points representing records in a database. The individual points can be represented as simple shapes and colors, but may…

state machine diagram

a visual representation of a series of “states” and transitions between those states, useful for modeling a wide variety of simple programming problems. Also called a “state transition diagram” or “transition network”.

statistical validity

the degree to which an observed result, such as a difference between 2 measurements, can be relied upon and not attributed to random error in sampling and measurement.

The degree of statistical significance of a result depends upon the number…

status line

a region on the screen, often at the base of a window, with general status information about the computer as a whole or the specific window or application. Typical information in status bars include:

…

steal and modify

a form of competitive analysis for design purposes. The idea is to find out how other systems have solved user interface design problems and adapt their solutions to your purposes.

stereopsis

the perception of depth based on the differences in images that reach the 2 eyes.

stickiness

the quality of a website that it retains visitors, by keeping them at the website and by getting them to return regularly.

Sticky Keys

a method of typing where modifier keys, such as Shift, Control, Command, and Alt/Option, will “stick” down and apply to the next keystroke, so that only one key needs to be pressed at a time. This is extremely useful for…

stimulus-response compatibility

the degree to which what people perceive is consistent with the actions they need to take.

Saying “red” when you see a red light go on is an example of high compatibility. Having to say “green” when a red light…

stone-paper-scissors

a model for game design in which the consequences of simultaneous actions are non-transitive. That is, no single action takes precedence over all others. This lends interest to a game by preventing any single strategy from being dominant in all…

storefront testing

opportunistic testing of an interface in a public location such as a storefront or other location where it’s easy to encounter target users because they are frequently in that location.

storyboard

a series of illustrations that represent a process, such as the steps of interacting with a computer or frames from an animation or movie. Storyboards are useful for presentations, such as with focus groups, and for checking that the steps…

stress testing

or “try-to-destroy-it” testing; testing the limits of a system based on the range of possible human interactions. Stress testing is especially appropriate to systems being used under extreme conditions: in public kiosks, unusual climates, for users who are unusually preoccupied…

stroke recognition

the conversion of pen strokes into text or computer commands. Thus, when someone enters handwriting, a computer can convert it to text. When they express certain gestures, it can be recognized as commands. For instance, a swiping gesture may be…

structural links

links made available to navigate an information space by its structure & not necessarily specifically related to the content of the page they’re found on.

struts and springs

a graphical way of representing layout constraints, used in some UIMS to handle the layout specifications for widgets. Struts and springs allow a programmer to specify minimum and maximum widths, proportions of the screen, alignment, and so forth.

style guide

a reference that establishes the look-and-feel of a user interface by clearly defining the standards and conventions of that user interface. Style guides usually include the principles that guide the design of the interface, graphic layout grids, exact size and…

subjective rating

any rating that a person gives that is based on their subjective reaction or opinion, their feelings, desires, priorities, etc. While the rating is subjective, it is often measured on a Likert scale, which allows for a quantitative measure that,…

subpane

or just “pane”; a window may be divided into multiple subpanes, each of which is typically devoted to different pieces of information. Subpanes are typically fixed in position with respect to the window as a whole. From a user’s view,…

surrogate users

people used as a substitute or representative for users, in order to provide information in design meetings, user testing, and so forth.

Typical surrogates would include managers, union reps, coworkers, friends, and designers (especially those who have interacted w/ users).…

survey

a technique for gathering information from a large number of users. A survey can be conducted through a large number of telephone interviews, a direct-mail questionnaire, or an online questionnaire. Major issues in survey design include:

…

symbol segmentation

automatically identifying the boundaries of individual meaningful units within a continuous input stream, such as a computer identifying individual words within spoken speech or identifying individual letters in handwriting. In simple circumstances, such as slowly and distinctly pronounced speech or…

synchronous groupware

same as “realtime groupware”; software used to help people to work in groups, while working together at the same time. The term synchronous is used to contrast this type of groupware with asynchronous groupware, which does not allow users to…

syntax-directed editor

a text editor, used primarily for writing software, that automatically formats the program code for readability based on its knowledge of the structure (the syntax) of the program. It may also simplify entering information by enabling the programmer to quickly…

synthetic metric

a value which is the result of combining other metrics, which are measurements of properties of designs, systems, or user performance. An example is to average the results of several subjective ratings scores that come from users responding to an…

system administration

supporting a user community by maintaining their computer environment, by handling such items as system purchasing and installation, software configuration, network configuration, backups, server maintenance, security, troubleshooting, user training, maintaining system stability, and providing technical support for users.

System administrators…