Accessibility, Usability and User Centred Design (Usabiltiy)

AccessibilityUsabilityUser centred designUsability2

ContentsUsability?Usability testingDiscount usabilityUsability adoption stagesDavid Lamas, TLU, 20102

Usability?David Lamas, TLU, 20103

UsabilityWhat?Why?When?Where?David Lamas, TLU, 20104

What is Usability?Usability is a quality attribute that assesses how easy user interfaces are to useThe wordusabilityalso refers to methods for improving ease-of-use during the design process but within this course’s context we will use it as a website’s quality attributeTo be usable, a product or service should be:UsefulEfficientEffectiveSatisfyingLearnable; andAccessibleDavid Lamas, TLU, 20105

What is Usability?Usefulness…concerns the degree to which a product enables a user to achieve his or her goals, and is an assessment of the user’s willingness to use the product at allWithout usefulness, other measures make no sense, because the product will just sit on the shelfIf a system is easy to use, easy to learn, and even satisfying to use, but does not achieve the specific goals of a specific user, it will not be used even if it is given away for freeInterestingly enough, usefulness is probably the element that is most often overlooked during experiments and studies in the labDavid Lamas, TLU, 20106

Usefulness, or the lack of itIn the early stages of product development, it is usually up to the marketing team to ascertain what product or system features are desirable and necessary before other elements of usability are even consideredLacking that, the development team is hard-pressed to take the user’s point of view and will simply guess or, even worse, use themselves as the user modelThis is very often where a system-oriented design takes holdJeffrey RubinWhat is Usability?David Lamas, TLU, 20107

What is Usability?Efficiency…relates to the quickness with which the user’s goal can be accomplished accurately and completely and is usually a measure of timeFor example, you might set a usability testing benchmark that says95% of all users will be able to load the software within 10 minutesDavid Lamas, TLU, 20108

What is Usability?Effectiveness…refers to the extent to which the product behaves in the way that users expect it to and the ease with which users can use it to do what they intendThis is usually measured quantitatively with error rateYour usability testing measure for effectiveness, like that for efficiency, should be tied to some percentage of total usersExtending the example from efficiency, the benchmark might be expressed as95% of all users will be able to load the software correctly on the first attemptDavid Lamas, TLU, 20109

What is Usability?Learnability…has to do with the user’s ability to operate the system to some defined level of competence after some predetermined amount and period of trainingIt can also refer to the ability of infrequent users to relearn the system after periods of inactivityDavid Lamas, TLU, 201010

What is Usability?Satisfaction…refers to the user’s perceptions, feelings, and opinions of the product, usually captured through both written and oral questioningUsers are more likely to perform well on a product that meets their needs andprovides satisfaction than one that does notTypically, users are asked to rate and rank products that they try, and this can often reveal causes and reasons for problems that occur David Lamas, TLU, 201011

What is Usability?AccessibilityNo need to go over this subject as it was already addressed last weekBut yes, this is where all accessibility issues would be accounted for in the broader usability scope of user centred designDavid Lamas, TLU, 201012

What is Usability?This means that usability goals and objectives are typically defined in measurable terms of one or more of the former attributesHowever, making a product usable is never simply the ability to generate numbers about usage, satisfaction, etc.While the numbers can tell us whether something works or notThere is a distinctive qualitative element to how usable something is which…is hard to capture with numbers; andis difficult to pin identifyhas to do with how one interprets the data in order to know how to fix a problem because the behavioral data tells you why there is a problemDavid Lamas, TLU, 201013

What is Usability?Unfortunately, usability is invisibleIf something is going well, you don’t notice itIf the temperature in a room is comfortable, no one complainsUsability happens along a continuumHow usable is your product?Could it be more usable even though users can accomplish their goals?Is it worth improving?Most usability professionals spend most of their time working on eliminating design problems, trying to minimize frustration for usersBut know that it is a difficult goal to attain for every user of your productIt affects only a small part of the user’s experience of accomplishing a goalAlthough there are quantitative approaches to testing the usability of products, it is impossible to measure the usability of somethingYou can only measure how unusable it is, how many problems people have using something, what the problems are and whyDavid Lamas, TLU, 201014

Why does usability fail?Common five reason for the delivery of less usable products are:Development focuses on the systemTarget audiences change and adaptDesigning usable products is difficultTeam specialists don’t always work in integrated waysDesign and implementation don’t always matchDavid Lamas, TLU, 201015

Why does usability fail?Development focuses on the systemDavid Lamas, TLU, 201016

Why does usability fail?Development focuses on the systemUnfortunately…Designers, engineers, and programmers have traditionally placed the greatest emphasis on the activity componentAnd much less emphasis on the human and the context componentsThe relationship of the three components to each other has also been neglectedThere is an underlying assumption that because humans are so flexible and adaptable, it is easier for them adapt themselves to the machine, than vice-versaDevelopers have historically been hired and rewarded not for their inter- personal skills but for their ability to solve technical problemsDesigners usually go about developing products for end users who were much like themselvesDavid Lamas, TLU, 201017

Why does usability fail?Target audiences change and adaptThe original users of computer-based products were enthusiasts possessingexpert knowledge of computersa love of technologythe desire to tinker, andpride in their ability to troubleshoot and repair any eventual problemDesigners and developers of these products shared similar characteristicsIn essence, users and developers of these systems were one and the sameNot anymore!Today’s user is not even remotely comparable to the designers and developers in skill set, aptitude, expectation, or almost any attribute that is relevant to the design process.David Lamas, TLU, 201018

Why does usability fail?Designing usable products is difficultPart art, part science, it seems that everyone has an opinion about usability, and how to achieve itThis trivializing of usability creates a more dangerous situation than if designers freely admitted that designing for usability was not their area of expertise and began to look for alternative ways of developing productsEveryone as an opinion until it is time to evaluate the usability of a productWhich requires…Operational definitions; andPrecise measurementsDavid Lamas, TLU, 201019

Why does usability fail?Team specialists don’t always work in integrated waysTo improve efficiency, many organizations have broken down the development process into separate componentsFor example…the user interfacethe help system, andthe written materialsThere is nothing inherently wrong with specializationThe difficulty arises when there is little integration of these separate components and poor communication among the different development teamsOr when organizations unknowingly exacerbate this lack of integration by usability testing each of the components separatelyDavid Lamas, TLU, 201020

Why does usability fail?Design and implementation don’t always matchThe design of the user interface and the technical implementation of the user interface are different activities, requiring very different skillsThis distinction was rarely acknowledged in the pastNowadays however, the challenge of design has increased dramatically due to the need to reach a broader, less sophisticated user population and the rising expectations for ease of useTo use a computer analogy, the focus has moved from how it works to how it communicatesDavid Lamas, TLU, 201021

Why should we care?On the Web…usability is a necessary condition for survivalIf a website is difficult to use, people leaveIf the landing page fails to clearly state what a company offers and what users can do on the site, they leaveIf users get lost on a website, they leaveIf a website's information is hard to read or doesn't answer users' key questions, they leaveThere's no such thing as a user reading a website manual or otherwise spending much time trying to figure out an interfaceThere are plenty of other websites availableLeaving is the first line of defense when users encounter a difficultyDavid Lamas, TLU, 201022

Why should we care?The first law of e-commerce is that if users cannot find the product, they cannot buy it either!David Lamas, TLU, 201023

Why should we care?Even for an internal audience such as what happens on an intranetUsability is a matter of employee productivityThe time users waste being lost on your intranet or trying to understand difficult instructions…is money being wasted by paying them to be at work without getting work done!David Lamas, TLU, 201024

Why should we care?According to Jakob Nielsen…Current best practices call for spending about 10% of a design project's budget on usabilityOn average, this will more than double a website's desired quality metrics and slightly less than double an intranet's quality metricsFor software and physical products, the improvements are typically smaller but still substantial when you emphasize usability in the design processDavid Lamas, TLU, 201025

Why should we care?e-CommerceThink of…doubling salesdoubling the number of registered users or customer leadsor doubling whatever other desired goal motivated your projectIntranetIn this case, think of doubling usability as cutting training budgets in half and doubling the number of transactions employees perform per hourDavid Lamas, TLU, 201026

When should we go about it?David Lamas, TLU, 201027

When should we go about it?Usability plays a role in each stage of the design process resulting in a need for multiple studiesThese are some of the the main usability testing opportunities:Before starting a new design, test the old design to identify the good parts that you should keep or emphasize, and the bad parts that give users troubleUnless you're working on an intranet, test your competitors' designs to get cheap data on a range of alternative interfaces that have similar features to your ownConduct a field study to see how users behave in their natural habitatMake paper prototypes of one or more new design ideas and test themThe less time you invest in these design ideas the better, because you'll need to change them all based on the test results.David Lamas, TLU, 201028

When should we go about it?And yet more of the the main usability testing opportunities:Refine the design ideas that test best through multiple iterations, gradually moving from low-fidelity prototyping to high-fidelity representationsTest each iterationInspect the design relative to established usability guidelines, whether from your own earlier studies or published standards and researchOnce you decide on and implement the final design, test it againSubtle usability problems always creep in during implementationDon't defer user testing until you have a fully implemented designIf you do, it will be difficult to fix the vast majority of the critical usability problems that the test uncovers.Many of these problems are likely to be structural, and fixing them would require major workThe only way to a high-quality user experience is to start user testing early in the design process and to keep testing every step of the way.David Lamas, TLU, 201029

Where?If usability tests are run at least once a week, it's worth building a dedicated usability laboratoryFor most companies, however, it's fine to conduct tests in a conference room or an officeAs long as you can close the door to keep out distractionsWhat matters is that you get hold of real users and sit with them while they use the designA notepad is the only equipment you need.David Lamas, TLU, 201030

Usability testingDavid Lamas, TLU, 201031

Usability testingUsability testing refers to the systematic experimental evaluation of the interaction between people and the products, equipment, environments, and services they use (McClelland 1995)It evaluates how easy a product is to use and whether it is functional and acceptable(Bogner 1998)Usability test results may not be valid unless the conditions of the test closely match those of actual product use(Cushman & Rosenberg 1991)Therefore, the operating characteristics of the prototype, the tasks, the duration of the test, and the environmental conditions must be realistic Both extreme and typical conditions should be included in the testDavid Lamas, TLU, 201032

Planning usability testingThe first decision is to establish the usability testing goal and options are…Formative usability testingFormative usability testing is iterative by natureQuestion might be about…The most significant usability issues preventing users from completing their tasksWhat works and what do they find frustratingWhat are the most common errors or mistakes users are makingAssessing the improvements being made from one design interaction to the nextWhat usability issues are expected to remain after the product is launchedSummative usability testingSummative testing might focus onassessing the usability of a finished product; orcomparing the usability of similar productsIn this case, questions are normally about…How some specific usability goals where meetHow does one product compare against the competitionAssessing improvements from one product release to the nextDavid Lamas, TLU, 201033

Planning usability testingThen, user goals must be identified and tasks devisedPerformancePerformance is about what a user does when interacting with a productIt is about how useful, efficient, effective, learnable and accessible a product isSatisfactionIts all about what a user says or thinks about her interaction with a productThis is something that should especially be accounted for on the user as something to say about using or not a specific productDavid Lamas, TLU, 201034

Planning usability testingSelecting the right kind of metrics is the third stepSelection of usability metrics should depend on the goal of the study as well as on the user’s goalsDavid Lamas, TLU, 201035

Planning usability testingDavid Lamas, TLU, 201036

Planning usability testingFinally, evaluation methods, participants and tools must be selectedEvaluation method options are…Lab testsA lab test involves one-on-one sessions between a moderator and the test participantsThe moderator asks questions and assigns tasks and notes the participant’s behaviour and responsesLab usability tests are normally formative in natureOnsite tests; andOnline testsDavid Lamas, TLU, 201037

Planning usability testingAs for participants,They have a major impact on usability testing findingsIt is critical that you plan how to include the most representative participants as possible in your studyThe steps you will go through in recruiting participants are essentially the same whether you are collecting metrics or notIf personas were used in de design process, then recruited participants should fall within the perceived user groupOtherwise, a general profile should be outlined and the participants should be recruited accordinglyIf a formative usability test is being run, a small number of participants is requiredSix are usually enough if no distinct user groups are foreseen, otherwise, each group should have at least 4 membersIf a summative usability test is being run, then the recommended number of participants number fall between 50 and 100A valid test might still be run with 20 participants but results can be pale in comparison to running the test with a larger set of usersDavid Lamas, TLU, 201038

Planning usability testingAs tools are concerned, they should be selected bearing in mind the data cleanup and data analysis tasks aheadDavid Lamas, TLU, 201039

MetricsPerformance metricsTask success Binary or gradedSuccess or FailureComplete success (with or without assistance), partial success (with or without assistance), Time on taskIs normally recorded for successfully accomplished tasksErrorsEfficiencyNormally a ratio between accomplishment and effortDifferent authors have established context specific formulas that should be accounted for before deciding on how to measure efficiencyLearnabilityPerformance metrics collected over time on distinct product trialsAt least two should be run in order to assess some lernabilityinicatorDavid Lamas, TLU, 201040

MetricsIssues-based metricsWhat is an issue?Anything that prevents task completionAnything that takes someone off-courseAnything that creates some level of confusionAnything that produces an errorNot seeing something that should be noticedAssuming something is correct when it is notPerforming the wrong actionMisinterpreting some piece of contentNot understanding the navigationHow are they identifiedNormally by analysing performance metric data eventually combinedDavid Lamas, TLU, 201041

Issues-based metricsAfter identified, issues usually classified according to their severitySmall impact on user experience, few users experiencing issueLow severitySmall impact on user experience, many users experiencing issueMedium severityLarge impact on user experience, few users experiencing issueMedium severityLarge impact on user experience, many users experiencing issueHigh severityDavid Lamas, TLU, 201042

MetricsAnd others exist such asSelf-reported metrics, used for assessing satisfaction among other participant perceived measuresBehavioural and physiological metricsof which eye-tracking is one of the most used ones as far as Web usability testing is concernedCombined and comparative metricsbased on combinations of the previously mentioned siblingsAnd others such as…Server logsCard-sorting dataOpen card sortingClosed card sortingAccessibility indicatorsDavid Lamas, TLU, 201043

How many users?When collecting usability metrics, testing 20 users typically offers a reasonably tight confidence intervalMany users are required because of the substantial individual differences in user performanceWhen you measure people, you'll always get some who are really fast and some who are really slowGiven this, you need to average these measures across a fairly large number of observations to smooth over the variabilityDavid Lamas, TLU, 201044

Large scale usability testingHaving said that testing on the region of 20 users offers a significant degree of confidence, in some cases you might want or need to run the test with a larger group of participantsThe main advantage of running a test with more participants is that as your sample size increases, so does your confidence in the dataLarge scale usability testing is normally summative in natureLarge scale usability testing is normally conducted remotelyUsing some sort of an online tool for task setting, user monitoring and data collectionDavid Lamas, TLU, 201045

Large scale usability testingLarge scale usability testing procedure should probably beCarefully planned; andShould probably be itself usability testedDavid Lamas, TLU, 201046

ToolsClickTaleClickTale is a paid hosted service that tracks user keystrokes, mouse clicks and moves and the time it takes for users to move around a web pageSingle user sessions are saved as a movie with a large round circle around the user’s cursor so it’s easier to seeA nice feature is the ability to show aggregated data in the form of heat maps or as reportsThe heat maps display red hot zones where most users spend longer periods, and blue or cold areas where your users spend the least amount of timeAnother nice feature is the Form Analytics tool which displays aggregate form field informationThis information includes time of field completion, the number of entries and clicks as well as which form fields have the highest abandonments, or take the longest to complete, or have the most back-tracks due to errors or confusion.David Lamas, TLU, 201047

ToolsClickTaleClick heat mapDavid Lamas, TLU, 201048

ToolsClickTaleAttention heat mapDavid Lamas, TLU, 201049

ToolsLoop11Loop11 is a unique usability testing tool in that it allows unmoderated remote usability testing using actual usersA researcher provides a simple task to a user, for example, finding a particular type of gift book for a relative on a book site, then tracking user interactionThe data is presented via reports of task completion rate, time on task, common fail pages, paths and a nice detailed path analysis for each users.Loop11 does not require software to be loaded on a web siteAs is mentioned on the Loop11 web site, this means remote unmoderated usability testing can be done on your competitor’s web siteBecause real users are being tested, Loop11’s results will be accurate, or at least as accurate as the real users are.David Lamas, TLU, 201050

ToolsLoop11Creating testsDavid Lamas, TLU, 201051

ToolsLoop11Getting resultsDavid Lamas, TLU, 201052

ToolsAnd many others are availableCheck Craig Tomlin’s list athttp://www.usefulusability.com/24-usability-testing-tools/David Lamas, TLU, 201053

Discount usabilityDavid Lamas, TLU, 201054

Discount usabilityUsability specialists will often propose using the best possible methodologyThis is what they have been trained to doUnfortunately, it seems that the best is the enemy of the good to the extent that insisting on using only the best methods may result in having no methods used at allDavid Lamas, TLU, 201055

Discount usabilityThe alternative is to use discount usability or… guerrilla usabilityGuerrilla usability is based on the use of the following three techniquesScenariosSimplified thinking aloudHeuristic evaluationAdditionally, the basic principle of early focus on users should of course be followedIt can be achieved in various ways, including simple visits to potential or future user locationsDavid Lamas, TLU, 201056

ScenariosScenarios are a kind of prototypingThe entire idea behind prototyping is to cut down on the complexity of implementation by eliminating parts of the full systemHorizontal prototypes reduce the level of functionality and result in a user interface surface layer, while vertical prototypes reduce the number of features and implement the full functionality of those chosenDavid Lamas, TLU, 201057horizontalprototypescenarioverticalprototype

ScenariosScenarios take prototyping to the extreme by reducing both the level of functionality and the number of featuresBy reducing the part of interface being considered to the minimum, a scenario can be very cheap to design and implement, but it is only able to simulate the user interface as long as a test user follows a previously planned pathSince the scenario is small, we can afford to change it frequently, and if we use cheap, small thinking aloud studies, we can also afford to test each of the versionsTherefore scenarios are a way of getting quick and frequent feedback from users.Scenarios can be implemented as paper mock-ups or in simple prototyping environmentsThis is an additional savings compared to more complex prototypes requiring the use of advanced software toolsDavid Lamas, TLU, 201058

Simplified thinking aloudThinking aloud studies are conducted with psychologists or user interface experts as experimenters who record the subjects actions and perform detailed protocol analysisHowever, it is possible to run user tests without sophisticated labs, simply by bringing in some real users, giving them some typical test tasks, and asking them to think out loud while they perform the tasksBesides reducing the number of subjects, another major difference between simplified and traditional thinking aloud is that data analysis can be done on the basis of the notes taken by the experimenter instead of by video footageDavid Lamas, TLU, 201059

Heuristic EvaluationCurrent standards and usability guidelines typically have on the order of one thousand rules to follow and are normally seen as intimidating by developersA discount alternative would be to use a small set of heuristics such as Jakob Nielsen’s ten basic usability principles David Lamas, TLU, 201060

Heuristic evaluationJakobNielsen´s ten basic usability heuristicsVisibility of system statusMatch between system and the real worldUser control and freedomConsistency and standardsError preventionRecognition rather than recallFlexibility and efficiency of useAesthetic and minimalist designHelp users recognize, diagnose, and recover from errorsHelp and documentationDavid Lamas, TLU, 201061

How many users?With this approach, the best results come from testing no more than 5 users and running as many small tests as you can affordDavid Lamas, TLU, 201062

ToolsMacSilverbackhttp://silverbackapp.com/PCCamtasiahttp://www.techsmith.com/camtasia.asp(there is also a Mac version)David Lamas, TLU, 201063

Usability adoption stagesJakob NielsenDavid Lamas, TLU, 201064

Stage 1Usability does not matterThe main focus is to bring every last bit of performance from the ironDavid Lamas, TLU, 201065

Stage 2Usability is importantbut good interfaces can surely be designed by the regular development staff as part of their general system designAt this stage, no attempt is made at user testing or at acquiring staff with usability expertiseDavid Lamas, TLU, 201066

Stage 3The desire to have the interface blessed by the magic wand of a usability engineerDevelopers recognize that they may not know everything about usability, so they call in a usability specialist to look over their design and comment on itThe involvement of the usability specialist is often too late to do much good in the project, and the usability specialist often has to provide advice on the interface without the benefit of access to real usersDavid Lamas, TLU, 201067

Stage 4Panic strikes, causing a sudden desire to learn about user interface issuesUnfortunately, the main concern is the to bring in usability specialists to advise on the graphic side of the user interfaces from the startSome usability specialists resent this attitude and maintain that it is more important to provide an appropriate interface for the task than to blindly go with a graphic design without prior task analysisEven so, this is an opportunity for usability specialists to get involved in the design process at an earlier stage than the traditional last-minute blessing of a design that cannot be changed muchDavid Lamas, TLU, 201068

Stage 5Discount usability engineering sporadically usedTypically, some projects use a few discount usability methods, though the methods are often used too late in the development lifecycle to do maximum goodProjects that do use usability methods often differ from others in having managers who have experienced the benefit of usability methods on earlier projectsThus, usability acts as a kind of virus, infecting progressively more projects as more people experience its benefitsDavid Lamas, TLU, 201069

Stage 6Discount usability engineering systematically usedAt some point in time, most projects involve some simple usability methods, and some projects even use usability methods in the early stages of system developmentScenarios and inexpensive prototyping techniques seem to be very effective weapons for guerrilla usability at this stageDavid Lamas, TLU, 201070

Stage 7Usability group or usability lab foundedMany companies decide to expand to a full scale usability approach after having experienced the benefits of discount usability engineeringTypically at this time, companies go aboutsetting up usability laboratories; orforming dedicated groups of usability specialistsDavid Lamas, TLU, 201071

Stage 8Usability permeates the lifecycleThe final stage is rarely reached since even companies with usability groups and usability labs normally do not have enough usability resources to employ all the methods one could wish for at all the stages of the development lifecycleHowever, there are some, often important, projects that have usability plans defined as part of their early project planning and where usability methods are used throughout the development lifecycleDavid Lamas, TLU, 201072

Usability In the endunderstanding what usability is all about fosters the development of a working for the greater good sense in all involved in a product’s life cycleUsability specialist or notDavid Lamas, TLU, 201073

ContentsUsability?Usability testingDiscount usabilityUsability adoption stagesDavid Lamas, TLU, 201074

Suggested viewingThe Design of Future Things http://www.youtube.com/watch?v=wQmwEjL6K1U&feature=PlayList&p=8C50465DE4A494CF&playnext_from=PL&playnext=1&index=11Don Norman talk at Stanford University (one of the gurus)Sketching and Experience Designhttp://www.youtube.com/watch?v=xx1WveKV7aE&feature=channelBill Buxton talk at Stanford University (not as good a presenter as Don Norman but very interesting and relevant)David Lamas, TLU, 201075

Elective readingsHollingsed, T. and Novick, D. G. 2007. Usability inspection methods after 15 years of research and practice. InProceedings of the 25th Annual ACM international Conference on Design of Communication (El Paso, Texas, USA, October 22 - 24, 2007). SIGDOC '07. ACM, New York, NY, 249-255.Sauro, J. and Kindlund, E. 2005. A method to standardize usability metrics into a single score. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (Portland, Oregon, USA, April 02 - 07, 2005). CHI '05. ACM, New York, NY, 401-409..Ivory, M. Y. and Hearst, M. A. 2001. The state of the art in automating usability evaluation of user interfaces. ACM Comput. Surv. 33, 4 (Dec. 2001), 470-516.Hornbæk, K. and Frøkjær, E. 2008. Making use of business goals in usability evaluation: an experiment with novice evaluators. In Proceeding of the Twenty-Sixth Annual SIGCHI Conference on Human Factors in Computing Systems(Florence, Italy, April 05 - 10, 2008). CHI '08. ACM, New York, NY, 903-912.Andreasen, M. S., Nielsen, H. V., Schrøder, S. O., and Stage, J. 2007. What happened to remote usability testing?: an empirical study of three methods. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems(San Jose, California, USA, April 28 - May 03, 2007). CHI '07. ACM, New York, NY, 1405-1414.Chiasson, S., Biddle, R., and van Oorschot, P. C. 2007. A second look at the usability of click-based graphical passwords. In Proceedings of the 3rd Symposium on Usable Privacy and Security (Pittsburgh, Pennsylvania, July 18 - 20, 2007). SOUPS '07, vol. 229. ACM, New York, NY, 1-12.Als, B. S., Jensen, J. J., and Skov, M. B. 2005. Comparison of think-aloud and constructive interaction in usability testing with children. In Proceedings of the 2005 Conference on interaction Design and Children (Boulder, Colorado, June 08 - 10, 2005). IDC '05. ACM, New York, NY, 9-16.Gould, J. D. and Lewis, C. 1985. Designing for usability: key principles and what designers think. Commun. ACM 28, 3 (Mar. 1985), 300-311.Dicks, R. S. 2002. Mis-usability: on the uses and misuses of usability testing. In Proceedings of the 20th Annual international Conference on Computer Documentation (Toronto, Ontario, Canada, October 20 - 23, 2002). SIGDOC '02. ACM, New York, NY, 26-30.David Lamas, TLU, 201076

Further readingsNiesen and Loranger 2006. Prioritizing Web usability, New RidersTullis and Albert 2008. Measuring the user experience, Morgan KaufmannAlbert et al. 2010. Beyond the usability lab, Morgan KaufmannDavid Lamas, TLU, 201077

Relevant linksDonald Norman’s websitehttp://www.jnd.org/books.htmlJakob Nielsen’s site on usabilityhttp://www.useit.com/(not always consensual)Jared Spool’s companyhttp://www.uie.com/(with links to interesting case studies)Steve Krug’s consultancy websitehttp://www.sensible.com/Bill Buxton’s websitehttp://www.billbuxton.com/US governmental usability support servicehttp://www.usability.gov/(as dull as a governmental service but rather useful )David Lamas, TLU, 201078

Accessibility, Usability and User Centred Design (Usabiltiy)

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Accessibility, Usability and User Centred Design (Usabiltiy)