系统可用性量表评估问卷

1、系统可用性量表评估问卷1中文:2，TheSystemUsabilityScale(SUS)wasoriginallycreatedasa“quickanddirty”scaleforadministeringafterusabilitytestsonsystemslikeVT100Terminal(“Green-Screen”)applications.SUSistechnologyindependentandhassincebeentestedonhardware,consumersoftware,websites,cell-phones,IVRsandeventheyellows.TheS

2、ystemUsabilityScaleTheSUSisa10itemquestionnairewith5responseoptions.IthinkthatIwouldliketousethissystemfrequently.Ifoundthesystemunnecessarilycomplex.Ithoughtthesystemwaseasytouse.IthinkthatIwouldneedthesupportofatechnicalpersontobeabletousethissystem.Ifoundthevariousfunctionsinthissystemwerewellint

3、egrated.Ithoughttherewastoomuchinconsistencyinthissystem.Iwouldimaginethatmostpeoplewouldlearntousethissystemveryquickly.Ifoundthesystemverycumbersometouse.Ifeltveryconfidentusingthesystem.IneededtolearnalotofthingsbeforeIcouldgetgoingwiththissystem.TheSUSusesthefollowingresponseformat:ScoringSUSFor

4、odditems:subtractonefromtheuserresponse.Foreven-numbereditems:subtracttheuserresponsesfrom5Thisscalesallvaluesfrom0to4(withfourbeingthemostpositiveresponse).Adduptheconvertedresponsesforeachuserandmultiplythattotalby2.5.Thisconvertstherangeofpossiblevaluesfrom0to100insteadoffrom0to40.InterpretingSUS

5、scoresDespitethewideusageofSUS,therehasbeenlittleguidanceoninterpretingSUSscores,acceptablemodificationstotheitemsandinformationonreliabilityandvalidity.OvertheyearsIveusedSUSalotinmyownresearchandduringusabilityevaluations.DuringthistimeIvereviewedtheexistingresearchonSUSandanalyzeddatafromover5000

6、usersacross500differentevaluations.ThisdatashowsthatSUSisareliableandvalidmeasureofperceivedusability.Itperformsaswellorbetterthancommercialquestionnairesandhome-growninternalquestionnaires.Iveputthesefindingsinawhichcontainsvaluableinsightsonbackground,benchmarksandbestpracticesforanyoneusingtheSUS

7、.Hereareafewhighlights.WhatisagoodSUSscore?TheaverageSUSscorefromall500studiesisa68.ASUSscoreabovea68wouldbeconsideredaboveaverageandanythingbelow68isbelowaverage.Thebestwaytointerpretyourscoreistoconvertittoapercentilerankthroughaprocesscallednormalizing.IvecreatedawhichtakesrawSUSscoresandgenerate

8、spercentileranksandletter-grades(fromA+toF)foreightdifferentapplicationtypes.ThegraphbelowshowshowthepercentileranksassociatewithSUSscoresandlettergrades.Thisprocessissimilartobasedonthedistributionofallscores.Forexample,arawSUSscoreofa74convertstoapercentilerankof70%.ASUSscoreof74hashigherperceived

9、usabilitythan70%ofallproductstested.ItcanbeinterpretedasagradeofaB-.Youdneedtoscoreabovean80.3togetanA(thetop10%ofscores).Thisisalsothepointwhereusersare.Scoringatthemeanscoreof68getsyouaCandanythingbelowa51isanF(puttingyouinthebottom15%).SUSscoresarenotpercentagesEventhoughaSUSscorecanrangefrom0to1

10、00,itisntapercentage.WhileitistechnicallycorrectthataSUSscoreof70outof100represents70%ofthepossiblemaximumscore,itsuggeststhescoreisatthe70thpercentile.Ascoreatthislevelwouldmeantheapplicationtestedisaboveaverage.Infact,ascoreof70isclosertotheaverageSUSscoreof68.Itisactuallymoreappropriatetocallit50

11、%.WhencommunicatingSUSscorestostakeholders,andespeciallythosewhoareunfamiliarwithSUS,itsbesttoconverttheoriginalSUSscoreintoapercentilesoa70%reallymeansaboveaverage.SUSmeasuresusabilityandlearnabilityWhileSUSwasonlyintendedtomeasureperceivedease-of-use(asingledimension),showsthatitprovidesaglobalmea

12、sureofsystemsatisfactionandsub-scalesofusabilityandlearnability.Items4and10providethelearnabilitydimensionandtheother8itemsprovidetheusabilitydimension.ThismeansyoucantrackandreportonbothsubscalesandtheglobalSUSscore.SUSisreliableReliabilityreferstohowconsistentlyusersrespondtotheitems(therepeatabil

13、ityoftheresponses).SUShasbeenshowntobemorereliableanddetectdifferencesatsmallersamplesizesthanhome-grownquestionnairesandothercommerciallyavailableones.Samplesizeandreliabilityareunrelated,soSUScanbeusedonverysmallsamplesizes(asfewastwousers)andstillgeneratereliableresults.However,smallsamplesizesge

14、nerateimpreciseestimatesoftheunknownuser-populationSUSscore.YoushouldcomputeaconfidenceintervalaroundyoursampleSUSscoretounderstandthevariabilityinyourestimate.SUSisvalidValidityreferstohowwellsomethingcanmeasurewhatitisintendedtomeasure.Inthiscasethatsperceivedusability.SUShasbeenshowntoeffectively

15、distinguishbetweenunusableandusablesystemsaswellasorbetterthanproprietaryquestionnaires.SUSalsocorrelateshighlywithotherquestionnaire-basedmeasurementsofusability(calledconcurrentvalidity).SUSisnotdiagnosticSUSwasnotintendedtodiagnoseusabilityproblems.Initsoriginaluse,SUSwasadministeredafterausabili

16、tytestwherealluser-sessionswererecordedonvideotape(VHSandBetamax).LowSUSscoresindicatedtotheresearchersthattheyneededtoreviewthetapeandidentifyproblemsencounteredwiththeinterface.SUScanbeusedoutsideofausabilitytestforbenchmarking,however,theresultswontshedmuchlightonwhyusersarerespondingthewaytheyar

17、e.ThereisamodestcorrelationbetweenSUSandtask-performanceUsersmayencounterproblems(evensevereproblems)withanapplicationandprovideSUSscoreswhichseemhigh.PosttestSUSscoresdocorrelatewithtaskperformance,althoughthecorrelationismodest(aroundr=.24forcompletionratesandtime),whichmeansthatonlyaround6%oftheS

18、USscoresareexplainedbywhathappensintheusabilitytest.Thisisthewithotherpost-testquestionnaires.QuickandnotsodirtyAtonly10items,SUSmaybequicktoadministerandscore,butdatafromover5000usersandalmost500differentstudiessuggeststhatSUSisfarfromdirty.Itsversatility,brevityandwide-usagemeansthatdespiteinevita

19、blechangesintechnology,wecanprobablycountonSUSbeingaroundforatleastanother30years.Wanttodivedeeper?JeffispresentingaseminaroninLondononJune15th2016.Thisisahalf-dayworkshopforresearchersanddesignerswhowanttousenumberstoinformdesignandmakebetterdecisionsaboutwebsites,softwareormobileapps.UsingSUSTheSUscaleisgenerallyusedaftertherespondenthashadanopportunitytousethesystembeingevaluated,butbeforeanydebriefingordiscussiontakesplace.Respondentsshouldbeaskedtorecordtheirimmediateresponsetoeachitem,ratherthanthinkingaboutitemsforalongt