Modern Systems Analysis and Design Third Edition 11 1 Selecting the Best Alternative Design Strategy Two basic steps Generate a comprehensive set of alternative design strategies Select the one design strategy that is most likely to result in the desired information system ID: 1020734
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1. Chapter 11Selecting the Best Alternative Design StrategyModern Systems Analysisand DesignThird Edition11.1
2. Selecting the Best Alternative Design StrategyTwo basic stepsGenerate a comprehensive set of alternative design strategiesSelect the one design strategy that is most likely to result in the desired information systemProcessDivide requirements into different sets of capabilitiesEnumerate different potential implementation environments that could be used to deliver the different sets of capabilitiesPropose different ways to source or acquire the various sets of capabilities for the different implementation environments11.2
3. Selecting the Best Alternative Design StrategyDeliverablesAt least three substantially different system design strategies for building the replacement information systemA design strategy judged most likely to lead to the most desirable information systemA Baseline Project Plan (BPP) for turning the most likely design strategy into a working information system11.3
4. Generating Alternative Design StrategiesBest to generate three alternatives Low-endProvides all required functionality users demand with a system that is minimally different from the current systemHigh-endSolves problem in question and provides many extra features users desireMidrangeCompromise of features of high-end alternative with frugality of low-end alternative11.4
5. Drawing Bounds on Alternative DesignsMinimum RequirementsMandatory features versus desired featuresForms of featuresDataOutputsAnalysesUser expectations on accessibility,response time and turnaround time11.5
6. Drawing Bounds on Alternative DesignsConstraints on System DevelopmentDate when system is neededFinancial and human resourcesElements of the system that cannot changeLegal and contractual considerations11.6
7. Issues to Consider in Generating AlternativesOutsourcingThe practice of turning over responsibility of some to all of an organization’s information systems applications and operations to an outside firmCan provide a cost effective solution11.7
8. Issues to Consider in Generating AlternativesSources of SoftwareHardware manufacturersPackaged software producersCustom software producersApplication Service ProvidersIn-house development11.8
9. Criteria for Choosing Off-the-Shelf SoftwareCostIn-House versus purchasedFunctionalityMandatory, essential and desired featuresVendor SupportInstallationTrainingTechnical Support11.9
10. Criteria for Choosing Off-the-Shelf SoftwareFlexibilityEase of customizationDocumentationUser documentationTechnical documentationResponse TimeEase of Installation11.10
11. Validating Purchased Software InformationInformation from vendorRequest for proposalA document provided to vendors to ask them to propose hardware and system software that will meet the requirements of your new systemSoftware evaluation periodCustomer references from vendorIndependent software testing service11.11
12. Hardware and Software IssuesExisting PlatformLower costsInformation system staff is familiar with operation and maintenanceNo added costs of converting old systems to new platform or transferring data New Hardware and System SoftwareSome software components will only run on new platformDeveloping system for new platform gives organization opportunity to upgrade technology holdingsNew requirements may allow organization to radically change its computing operations11.12