usability userfriendly redirects here for the webcomic see user friendly for other uses see user friendly disambiguation usable redirects here for the idea contest see usable many tools are designed to be easy to hold and use for their intended purpose for example a screwdriver typically has a handle with rounded edges and a grippable surface to make it easier for the user to hold the handle and twist it to drive a screw usability is the ease of use and learnability of a humanmade object such as a tool or device the object of use can be a software application website book tool machine process vehicle or anything a human interacts with a usability study may be conducted as a primary job function by a usability analyst or as a secondary job function by designers technical writers marketing personnel and others it is widely used in consumer electronics communication and knowledge transfer objects such as a cookbook a document or online help and mechanical objects such as a door handle or a hammer usability includes methods of measuring usability such as needs analysis introduction the primary notion of usability is that an object designed with a generalized users psychology and physiology in mind is for example more efficient to usetakes less time to accomplish a particular task easier to learnoperation can be learned by observing the object more satisfying to use complex computer systems find their way into everyday life and at the same time the market is saturated with competing brands this has made usability more popular and widely recognized in recent years as companies see the benefits of researching and developing their products with useroriented methods instead of technologyoriented methods by understanding and researching the interaction between product and user the usability expert can also provide insight that is unattainable by traditional companyoriented market research for example after observing and interviewing users the usability expert may identify needed functionality or design flaws that were not anticipated a method called contextual inquiry does this in the naturally occurring context of the users own environment in the usercentered design paradigm the product is designed with its intended users in mind at all times in the userdriven or participatory design paradigm some of the users become actual or de facto members of the design team the term user friendly is often used as a synonym for usable though it may also refer to accessibility usability describes the quality of user experience across websites software products and environments there is no consensus about the relation of the terms ergonomics or human factors and usability some think of usability as the software specialization of the larger topic of ergonomics others view these topics as tangential with ergonomics focusing on physiological matters eg turning a door handle and usability focusing on psychological matters eg recognizing that a door can be opened by turning its handle usability is also important in website development web usability according to jakob nielsen studies of user behavior on the web find a low tolerance for difficult designs or slow sites people dont want to wait and they dont want to learn how to use a home page theres no such thing as a training class or a manual for a web site people have to be able to grasp the functioning of the site immediately after scanning the home pagefor a few seconds at most otherwise most casual users simply leave the site and browse or shop elsewhere definition iso defines usability as the extent to which a product can be used by specified users to achieve specified goals with effectiveness efficiency and satisfaction in a specified context of use the word usability also refers to methods for improving easeofuse during the design process usability consultant jakob nielsen and computer science professor ben shneiderman have written separately about a framework of system acceptability where usability is a part of usefulness and is composed of learnability how easy is it for users to accomplish basic tasks the first time they encounter the design efficiency once users have learned the design how quickly can they perform tasks memorability when users return to the design after a period of not using it how easily can they reestablish proficiency errors how many errors do users make how severe are these errors and how easily can they recover from the errors satisfaction how pleasant is it to use the design usability is often associated with the functionalities of the product cf iso definition below in addition to being solely a characteristic of the user interface cf framework of system acceptability also below which separates usefulness into usability and utility for example in the context of mainstream consumer products an automobile lacking a reverse gear could be considered unusable according to the former view and lacking in utility according to the latter view when evaluating user interfaces for usability the definition can be as simple as the perception of a target user of the effectiveness fit for purpose and efficiency work or time required to use of the interface each component may be measured subjectively against criteria eg principles of user interface design to provide a metric often expressed as a percentage it is important to distinguish between usability testing and usability engineering usability testing is the measurement of ease of use of a product or piece of software in contrast usability engineering ue is the research and design process that ensures a product with good usability usability is a nonfunctional requirement as with other nonfunctional requirements usability cannot be directly measured but must be quantified by means of indirect measures or attributes such as for example the number of reported problems with easeofuse of a system intuitive interfaces see also natural user interface the term intuitive is often listed as a desirable trait in usable interfaces often used as a synonym for learnable some experts such as jef raskin have discouraged using this term in user interface design claiming that easy to use interfaces are often easy because of the users exposure to previous similar systems thus the term familiar should be preferred instead he advocates the term intuitable ie that users could intuit the workings of an application by seeing it and using it he continues however but even that is a less than useful goal since only 25 percent of the population depends on intuition to perceive anything iso standards isotr 169822002 standard isotr 169822002 ergonomics of humansystem interactionusability methods supporting humancentered design is an international standards organization iso standard that provides information on humancentered usability methods that can be used for design and evaluation it details the advantages disadvantages and other factors relevant to using each usability method it explains the implications of the stage of the life cycle and the individual project characteristics for the selection of usability methods and provides examples of usability methods in context the main users of isotr 169822002 are project managers it therefore addresses technical human factors and ergonomics issues only to the extent necessary to allow managers to understand their relevance and importance in the design process as a whole the guidance in isotr 169822002 can be tailored for specific design situations by using the lists of issues characterizing the context of use of the product to be delivered selection of appropriate usability methods should also take account of the relevant lifecycle process isotr 169822002 is restricted to methods that are widely used by usability specialists and project managers it does not specify the details of how to implement or carry out the usability methods described iso 9241 standard iso 9241 is a multipart standard that covers a number of aspects of people working with computers although originally titled ergonomic requirements for office work with visual display terminals vdts it has been retitled to the more generic ergonomics of human system interaction designing for usability see also usability engineering any system or device designed for use by people should be easy to use easy to learn easy to remember the instructions and helpful to users john gould and clayton lewis recommend that designers striving for usability follow these three design principles early focus on end users and the tasks they need the systemdevice to do empirical measurement using quantitative or qualitative measures iterative design in which the designers work in a series of stages improving the design each time early focus on users and tasks the design team should be userdriven and it should be in direct contact with potential users several evaluation methods including personas cognitive modeling inspection inquiry prototyping and testing methods may contribute to understanding potential users and their perceptions of how well the product or process works usability considerations such as who the users are and their experience with similar systems must be examined as part of understanding users this knowledge must be played against the tasks that the users will be expected to perform empirical measurement test the system early on and test the system on real users using behavioral measurements this includes testing the system for both learnability and usability see evaluation methods it is important in this stage to use quantitative usability specifications such as time and errors to complete tasks and number of users to test as well as examine performance and attitudes of the users testing the system iterative design iterative design is a design methodology based on a cyclic process of prototyping testing analyzing and refining a product or process based on the results of testing the most recent iteration of a design changes and refinements are made this process is intended to ultimately improve the quality and functionality of a design in iterative design interaction with the designed system is used as a form of research for informing and evolving a project as successive versions or iterations of a design are implemented the key requirements for iterative design are identification of required changes an ability to make changes and a willingness to make changes when a problem is encountered there is no set method to determine the correct solution rather there are empirical methods that can be used during system development or after the system is delivered usually a more inopportune time ultimately iterative design works towards meeting goals such as making the system user friendly easy to use easy to operate simple etc evaluation methods there are a variety of usability evaluation methods certain methods use data from users while others rely on usability experts there are usability evaluation methods for all stages of design and development from product definition to final design modifications when choosing a method consider cost time constraints and appropriateness for a brief overview of methods see comparison of usability evaluation methods or continue reading below usability methods can be further classified into the subcategories below cognitive modeling methods cognitive modeling involves creating a computational model to estimate how long it takes people to perform a given task models are based on psychological principles and experimental studies to determine times for cognitive processing and motor movements cognitive models can be used to improve user interfaces or predict problem errors and pitfalls during the design process a few examples of cognitive models include parallel design with parallel design several people create an initial design from the same set of requirements each person works independently and when finished shares concepts with the group the design team considers each solution and each designer uses the best ideas to further improve their own solution this process helps generate many different diverse ideas and ensures that the best ideas from each design are integrated into the final concept this process can be repeated several times until the team is satisfied with the final concept goms goms goms stands for goals operator methods and selection rules it is a family of techniques that analyzes the user complexity of interactive systems goals are what the user must accomplish an operator is an action performed in pursuit of a goal a method is a sequence of operators that accomplish a goal selection rules specify which method satisfies a given goal based on context human processor model human processor model sometimes it is useful to break a task down and analyze each individual aspect separately this helps the tester locate specific areas for improvement to do this it is necessary to understand how the human brain processes information a model of the human processor is shown below many studies have been done to estimate the cycle times decay times and capacities of each of these processors variables that affect these can include subject age aptitudes ability and the surrounding environment for a younger adult reasonable estimates are parameter mean range eye movement time 230 ms 70700 ms decay halflife of visual image storage 200 ms 901000 ms perceptual processor cycle time 100 ms 50200 ms cognitive processor cycle time 70 ms 25170 ms motor processor cycle time 70 ms 30100 ms effective working memory capacity 2 items 23 items longterm memory is believed to have an infinite capacity and decay time keystroke level modeling keystroke level model keystroke level modeling is essentially a less comprehensive version of goms that makes simplifying assumptions in order to reduce calculation time and complexity inspection methods usability inspection these usability evaluation methods involve observation of users by an experimenter or the testing and evaluation of a program by an expert reviewer they provide more quantitative data as tasks can be timed and recorded card sorts card sorting is a way to involve users in grouping information for a websites usability review participants in a card sorting session are asked to organize the content from a web site in a way that makes sense to them participants review items from a web site and then group these items into categories card sorting helps to learn how users think about the content and how they would organize the information on the web site card sorting helps to build the structure for a web site decide what to put on the home page and label the home page categories it also helps to ensure that information is organized on the site in a way that is logical to users tree tests tree testing is a way to evaluate the effectiveness of a websites topdown organization participants are given find it tasks then asked to drill down through successive text lists of topics and subtopics to find a suitable answer tree testing evaluates the findability and labeling of topics in a site separate from its navigation controls or visual design ethnography ethnographic analysis is derived from anthropology field observations are taken at a site of a possible user which track the artifacts of work such as postit notes items on desktop shortcuts and items in trash bins these observations also gather the sequence of work and interruptions that determine the users typical day heuristic evaluation heuristic evaluation is a usability engineering method for finding and assessing usability problems in a user interface design as part of an iterative design process it involves having a small set of evaluators examining the interface and using recognized usability principles the heuristics it is the most popular of the usability inspection methods as it is quick cheap and easy heuristic evaluation was developed to aid in the design of computer userinterface design it relies on expert reviewers to discover usability problems and then categorize and rate them by a set of principles heuristics it is widely used based on its speed and costeffectiveness jakob nielsens list of ten heuristics is the most commonly used in industry these are ten general principles for user interface design they are called heuristics because they are more in the nature of rules of thumb than specific usability guidelines visibility of system status the system should always keep users informed about what is going on through appropriate feedback within reasonable time match between system and the real world the system should speak the users language with words phrases and concepts familiar to the user rather than systemoriented terms follow realworld conventions making information appear in a natural and logical order user control and freedom users often choose system functions by mistake and will need a clearly marked emergency exit to leave the unwanted state without having to go through an extended dialogue support undo and redo consistency and standards users should not have to wonder whether different words situations or actions mean the same thing follow platform conventions error prevention even better than good error messages is a careful design that prevents a problem from occurring in the first place either eliminate errorprone conditions or check for them and present users with a confirmation option before they commit to the action recognition rather than recall minimize the users memory load by making objects actions and options visible the user should not have to remember information from one part of the dialogue to another instructions for use of the system should be visible or easily retrievable whenever appropriate flexibility and efficiency of use acceleratorsunseen by the novice usermay often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users allow users to tailor frequent actions aesthetic and minimalist design dialogues should not contain information that is irrelevant or rarely needed every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility help users recognize diagnose and recover from errors error messages should be expressed in plain language no codes precisely indicate the problem and constructively suggest a solution help and documentation even though it is better if the system can be used without documentation it may be necessary to provide help and documentation any such information should be easy to search focused on the users task list concrete steps to be carried out and not be too large thus by determining which guidelines are violated the usability of a device can be determined usability inspection usability inspection is a review of a system based on a set of guidelines the review is conducted by a group of experts who are deeply familiar with the concepts of usability in design the experts focus on a list of areas in design that have been shown to be troublesome for users pluralistic inspection pluralistic inspections are meetings where users developers and human factors people meet together to discuss and evaluate step by step of a task scenario as more people inspect the scenario for problems the higher the probability to find problems in addition the more interaction in the team the faster the usability issues are resolved consistency inspection in consistency inspection expert designers review products or projects to ensure consistency across multiple products to look if it does things in the same way as their own designs activity analysis activity analysis is a usability method used in preliminary stages of development to get a sense of situation it involves an investigator observing users as they work in the field also referred to as user observation it is useful for specifying user requirements and studying currently used tasks and subtasks the data collected are qualitative and useful for defining the problem it should be used when you wish to frame what is needed or what do we want to know inquiry methods the following usability evaluation methods involve collecting qualitative data from users although the data collected is subjective it provides valuable information on what the user wants task analysis task analysis means learning about users goals and users ways of working task analysis can also mean figuring out what more specific tasks users must do to meet those goals and what steps they must take to accomplish those tasks along with user and task analysis a third analysis is often used understanding users environments physical social cultural and technological environments focus groups a focus group is a focused discussion where a moderator leads a group of participants through a set of questions on a particular topic although typically used as a marketing tool focus groups are sometimes used to evaluate usability used in the product definition stage a group of 6 to 10 users are gathered to discuss what they desire in a product an experienced focus group facilitator is hired to guide the discussion to areas of interest for the developers focus groups are typically videotaped to help get verbatim quotes and clips are often used to summarize opinions the data gathered is not usually quantitative but can help get an idea of a target groups opinion questionnairessurveys surveys have the advantages of being inexpensive require no testing equipment and results reflect the users opinions when written carefully and given to actual users who have experience with the product and knowledge of design surveys provide useful feedback on the strong and weak areas of the usability of a design this is a very common method and often does not appear to be a survey but just a warranty card prototyping methods it is often very difficult for designers to conduct usability tests with the exact system being designed cost constraints size and design constraints usually lead the designer to creating a prototype of the system instead of creating the complete final system the designer may test different sections of the system thus making several small models of each component of the system the types of usability prototypes may vary from using paper models index cards hand drawn models or storyboards prototypes are able to be modified quickly often are faster and easier to create with less time invested by designers and are more apt to change design although sometimes are not an adequate representation of the whole system are often not durable and testing results may not be parallel to those of the actual system rapid prototyping rapid prototyping is a method used in early stages of development to validate and refine the usability of a system it can be used to quickly and cheaply evaluate userinterface designs without the need for an expensive working model this can help remove hesitation to change the design since it is implemented before any real programming begins one such method of rapid prototyping is paper prototyping testing methods usability testing these usability evaluation methods involve testing of subjects for the most quantitative data usually recorded on video they provide task completion time and allow for observation of attitude regardless to how carefully a system is designed all theories must be tested using usability tests usability tests involve typical users using the system or product in a realistic environment observation of the users behavior emotions and difficulties while performing different tasks often identify areas of improvement for the system metrics while conducting usability tests designers must use usability metrics to identify what it is they are going to measure or the usability metrics these metrics are often variable and change in conjunction with the scope and goals of the project the number of subjects being tested can also affect usability metrics as it is often easier to focus on specific demographics qualitative design phases such as general usability can the task be accomplished and user satisfaction are also typically done with smaller groups of subjects using inexpensive prototypes on small user groups provides more detailed information because of the more interactive atmosphere and the designers ability to focus more on the individual user as the designs become more complex the testing must become more formalized testing equipment will become more sophisticated and testing metrics become more quantitative with a more refined prototype designers often test effectiveness efficiency and subjective satisfaction by asking the user to complete various tasks these categories are measured by the percent that complete the task how long it takes to complete the tasks ratios of success to failure to complete the task time spent on errors the number of errors rating scale of satisfactions number of times user seems frustrated etc after conducting usability tests it is important for a designer to record what was observed in addition to why such behavior occurred and modify the model according to the results often it is quite difficult to distinguish the source of the design errors and what the user did wrong however effective usability tests will not generate a solution to the problems but provide modified design guidelines for continued testing remote usability testing remote usability testing also known as unmoderated or asynchronous usability testing involves the use of a specially modified online survey allowing the quantification of user testing studies by providing the ability to generate large sample sizes or a deep qualitative analysis without the need for dedicated facilities additionally this style of user testing also provides an opportunity to segment feedback by demographic attitudinal and behavioral type the tests are carried out in the users own environment rather than labs helping further simulate reallife scenario testing this approach also provides a vehicle to easily solicit feedback from users in remote areas there are two types quantitative or qualitative quantitative use large sample sized and task based surveys these types of studies are useful for validating suspected usability issues qualitative studies are best used as exploratory research in small sample sizes but frequent even daily iterations qualitative usually allows for observing respondents screens and verbal think aloud commentary screen recording video srv and for a richer level of insight also include the webcam view of the respondent videoinvideo viv sometimes referred to as pictureinpicture pip remote usability testing for mobile devices the growth in mobile and associated platforms and services eg mobile gaming has experienced 20x growth in 20102012 has generated a need for unmoderated remote usability testing on mobile devices both for websites but especially for app interactions one methodology consists of shipping cameras and special camera holding fixtures to dedicated testers and having them record the screens of the mobile smartphone or tablet device usually using an hd camera a drawback of this approach is that the finger movements of the respondent can obscure the view of the screen in addition to the bias and logistical issues inherent in shipping special hardware to selected respondents a newer approach uses a wireless projection of the mobile device screen onto the computer desktop screen of the respondent who can then be recorded through their webcam and thus a combined videoinvideo view of the participant and the screen interactions viewed simultaneously while incorporating the verbal think aloud commentary of the respondents thinking aloud the think aloud protocol is a method of gathering data that is used in both usability and psychology studies it involves getting a user to verbalize their thought processes as they perform a task or set of tasks often an instructor is present to prompt the user into being more vocal as they work similar to the subjectsintandem method it is useful in pinpointing problems and is relatively simple to set up additionally it can provide insight into the users attitude which can not usually be discerned from a survey or questionnaire rite method rapid iterative testing and evaluation rite is an iterative usability method similar to traditional discount usability testing the tester and team must define a target population for testing schedule participants to come into the lab decide on how the users behaviors will be measured construct a test script and have participants engage in a verbal protocol eg think aloud however it differs from these methods in that it advocates that changes to the user interface are made as soon as a problem is identified and a solution is clear sometimes this can occur after observing as few as 1 participant once the data for a participant has been collected the usability engineer and team decide if they will be making any changes to the prototype prior to the next participant the changed interface is then tested with the remaining users subjectsintandem or codiscovery subjectsintandem also called codiscovery is the pairing of subjects in a usability test to gather important information on the ease of use of a product subjects tend to discuss the tasks they have to accomplish out loud and through these discussions observers learn where the problem areas of a design are to encourage cooperative problemsolving between the two subjects and the attendant discussions leading to it the tests can be designed to make the subjects dependent on each other by assigning them complementary areas of responsibility eg for testing of software one subject may be put in charge of the mouse and the other of the keyboard componentbased usability testing componentbased usability testing is an approach which aims to test the usability of elementary units of an interaction system referred to as interaction components the approach includes componentspecific quantitative measures based on user interaction recorded in log files and componentbased usability questionnaires other methods cognitive walk through cognitive walkthrough is a method of evaluating the user interaction of a working prototype or final product it is used to evaluate the systems ease of learning cognitive walk through is useful to understand the users thought processes and decision making when interacting with a system specially for firsttime or infrequent users benchmarking benchmarking creates standardized test materials for a specific type of design four key characteristics are considered when establishing a benchmark time to do the core task time to fix errors time to learn applications and the functionality of the system once there is a benchmark other designs can be compared to it to determine the usability of the system many of the common objectives of usability studies such as trying to understand user behavior or exploring alternative designs must be put aside unlike many other usability methods or types of labs studies benchmark studies more closely resemble true experimental psychology lab studies with greater attention to detail on methodology study protocol and data analysis metaanalysis metaanalysis is a statistical procedure to combine results across studies to integrate the findings this phrase was coined in 1976 as a quantitative literature review this type of evaluation is very powerful for determining the usability of a device because it combines multiple studies to provide very accurate quantitative support persona personas are fictitious characters created to represent a site or products different user types and their associated demographics and technographics alan cooper introduced the concept of using personas as a part of interactive design in 1998 in his book the inmates are running the asylum benefits the key benefits of usability are higher revenues through increased sales increased user efficiency and user satisfaction reduced development costs reduced support costs corporate integration an increase in usability generally positively affects several facets of a companys output quality in particular the benefits fall into several common areas increased productivity decreased training and support costs increased sales and revenues reduced development time and costs reduced maintenance costs increased customer satisfaction increased usability in the workplace fosters several responses from employees workers who enjoy their work do it better stay longer in the face of temptation and contribute ideas and enthusiasm to the evolution of enhanced productivity working posture design of workstation furniture screen displays input devices organization issues office environment software interface by working to improve said factors corporations can achieve their goals of increased output at lower costs while potentially creating optimal levels of customer satisfaction there are numerous reasons why each of these factors correlates to overall improvement for example making software user interfaces easier to understand reduces the need for extensive training the improved interface tends to lower the time needed to perform tasks and so would both raise the productivity levels for employees and reduce development time and thus costs each of the aforementioned factors are not mutually exclusive rather they should be understood to work in conjunction to form the overall workplace environment in the 2010s usability is recognized as an important software quality attribute earning its place among more traditional attributes such as performance robustness and aesthetic appearance various academic programs focus on usability several usability consultancy companies have emerged and traditional consultancy and design firms offer similar services there is some resistance to integrating usability work in organisations usability is seen as a vague concept it is difficult to measure and other areas are prioritised when it projects run out of time or money professional development usability practitioners are sometimes trained as industrial engineers psychologists kinesiologists systems design engineers or with a degree in information architecture information or library science or humancomputer interaction hci more often though they are people who are trained in specific applied fields who have taken on a usability focus within their organization anyone who aims to make tools easier to use and more effective for their desired function within the context of work or everyday living can benefit from studying usability principles and guidelines for those seeking to extend their training the usability professionals association offers online resources reference lists courses conferences and local chapter meetings the upa also sponsors world usability day each november accessibility chief experience officer cxo design for all inclusion experience design fittss law form follows function gemba or customer visit goms gotcha programming gui human factors information architecture interaction design interactive systems engineering internationalization learnability list of humancomputer interaction topics list of system quality attributes machinereadable documents natural mapping interface design needs analysis rite method system usability scale universal usability usability goals usability testing usability engineering user experience user experience design web usability world usability day r g bias and d j mayhew eds 2005 costjustifying usability an update for the internet age morgan kaufmann donald a norman 2013 the design of everyday things basic books isbn0465072992 donald a norman 2004 emotional design why we love or hate everyday things basic books isbn0465051367 jakob nielsen 1994 usability engineering morgan kaufmann publishers isbn0125184069 jakob nielsen 1994 usability inspection methods john wiley sons isbn0471018775 ben shneiderman software psychology 1980 isbn0876268165 look up usability in wiktionary the free dictionary usabilitygov vteengineering approachesschool empathic design frugal innovation kansei engineering keep it simple stupid minimalism usecentered design usercentered design concepts ornament and crime overengineering planned obsolescence sustainability theory of constraints usability authority control gnd 40055413 ndl 01001766 