Bài giảng Systems Analysis and Design - Chapter 5: Information Gathering: Unobtrusive Methods

Information Gathering: Unobtrusive MethodsSystems Analysis and Design, 7eKendall & Kendall5© 2008 Pearson Prentice HallLearning ObjectivesRecognize the value of unobtrusive methods for information gatheringUnderstand the concept of sampling for human information requirements analysisConstruct useful samples of people, documents, and events for determining human information requirementsCreate an analyst’s playscript to observe decision-maker activitiesApply the STROBE technique to observe and interpret the decision-maker’s environment and their interaction with technologies2Unobtrusive Methods Less disruptiveInsufficient when used aloneMultiple methods approachUsed in conjunction with interactive methods3Major TopicsSamplingQuantitative document analysisQualitative document analysisObservationSTROBEApplying STROBE4SamplingA process of systematically selecting representative elements of a populationInvolves two key decisions:What to examineWhich people to consider5Need for Sampling The reasons systems analysts do sampling are:Containing costsSpeeding up the data gatheringImproving effectivenessReducing bias6Sampling DesignTo design a good sample, a systems analyst must follow four steps:Determining the data to be collected or describedDetermining the population to be sampledChoosing the type of sampleDeciding on the sample size7Figure 5.1 Four main types of samples the analyst has available8The Sample Size DecisionDetermine the attributeLocate the database or reports in which the attribute can be foundExamine the attributeMake the subjective decision regarding the acceptable interval estimateChoose the confidence levelCalculate the standard errorDetermine the sample size9Figure 5.2 A table of area under a normal curve can be used to look up a value once the systems analyst decides on the confidence level10Calculate the Standard Error of the Proportionsp = i/zi = interval estimatez = confidence coefficient found in the confidence level lookup table11 p(1-p)n = + 1 σp2Determine the Sample Sizeσp = standard errorρ = the proportion of the population having the attribute12Example: A. Sembly CompanyDetermine that you are looking for orders with mistakes Locate order forms from the past six monthsExamine order forms and conclude that p=5% Subjective decision of acceptable interval i = ± 0.02 Look up confidence coefficient z-value = 1.96 Calculate sp = i / z = 0.02/1.96 = 0.0102 Determine n; n = 45813InvestigationThe act of discovery and analysis of dataHard dataQuantitativeQualitative14Analyzing Quantitative DocumentsReports used for decision makingPerformance reportsRecordsData capture formsEcommerce and other transactions15Reports Used for Decision MakingSales reportsProduction reportsSummary reports16Figure 5.3 A performance report showing improvement17Figure 5.4 A manually completed payment record18Data Capture FormsCollect examples of all the forms in useNote the type of formDocument the intended distribution patternCompare the intended distribution pattern with who actually receives the form19Figure 5.5 Questions to ask about official and bootleg forms that are already filled out20Analyzing Qualitative DocumentsKey or guiding metaphorsInsiders vs. outsiders mentalityWhat is considered good vs. evilGraphics, logos, and icons in common areas or Web pagesA sense of humor21Analyzing Qualitative DocumentsEmail messages and memosSigns or posters on bulletin boardsCorporate Web sitesManualsPolicy handbooks22Figure 5.6 Analysis of memos provides insight into the metaphors that guide the organization’s thinking23Figure 5.7 Posted signs reveal the official organizational culture24ObservationObservation provides insight on what organizational members actually doSee firsthand the relationships that exist between decision makers and other organizational membersCan also reveal important clues regarding HCI concerns25Analyst’s PlayscriptInvolves observing the decision-makers behavior and recording their actions using a series of action verbsExamples:TalkingSamplingCorrespondingDeciding26Figure 5.8 A sample page from the analyst’s playscript describing decision making27STROBE STRuctured OBservation of the Environment—a technique for observing the decision-maker's physical environment28STROBE ElementsOffice locationDesk placementStationary equipmentPropsExternal information sourcesOffice lighting and colorClothing worn by decision makers29Office LocationAccessible officesMain corridors, open doorMajor traffic flow areaIncrease interaction frequency and informal messagesInaccessible officesMay view the organization differentlyDrift apart from others in objectives30Desk PlacementVisitors in a tight space, back to wall, large expanse behind deskIndicates maximum power positionDesk facing the wall, chair at sideEncourages participationEqual exchanges31Stationary Office EquipmentFile cabinets and bookshelves:If not present, person stores few items of information personallyIf an abundance, person stores and values information32PropsCalculatorsPersonal computersPens, pencils, and rulersIf present, person processes data personally33External Information SourcesTrade journals or newspapers indicate the person values outside informationCompany reports, memos, policy handbooks indicate the person values internal information34Office Lighting and ColorWarm, incandescent lighting indicates:A tendency toward more personal communicationMore informal communicationBrightly lit, bright colors indicate:More formal communications (memos, reports)35ClothingMaleFormal two-piece suit - maximum authorityCasual dressing (sport jacket/slacks) - more participative decision makingFemaleSkirted suit - maximum authority36Figure 5.10 Observe a decision maker’s office for clues concerning his or her personal storage, processing, and sharing of information37Applying STROBEThe five symbols used to evaluate how observation of the elements of STROBE compared with interview results are:A checkmark, the narrative is confirmedAn “X” means the narrative is reversedAn oval or eye-shaped symbol serves as a cue to look furtherA square means observation modifies the narrativeA circle means narrative is supplemented by observation38Figure 5.12 An anecdotal list with symbols for use in applying STROBE39SummarySamplingDesigning a good sampleTypes of samplesSample sizeHard dataQuantitative document analysisQualitative document analysisObservationPlayscriptSTROBESTROBE elementsApplying STROBE40