Slide 1 Introduction to Systems Analysis and Design

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Introduction to Systems Analysis and Design

Chapter 1

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Key Ideas

More than ½ of all IS development projects Fail.

Canceled before completionSystem is never used once finishedDoesn't provide the expected benefits

Most of the ones that don't fail:Are delivered lateAre over budgetDon't provide the features promised

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Key Ideas

Many fail because analysts try to build wonderful systems without understanding the organization.The primarily goal is to create value for the organization.

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Key Ideas

The systems analyst is a key person analyzing the business, identifying opportunities for improvement, and designing information systems to implement these ideas.It is important to understand and develop through practice the skills needed to successfully design and implement new information systems.

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THE SYSTEMS DEVELOPMENT LIFE CYCLE

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Major Attributes of the Lifecycle

The projectMoves systematically through phases where each phase has a standard set of outputsProduces project deliverablesUses deliverables in implementationResults in actual information systemUses gradual refinement

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Project Phases

PlanningWhy build the system?

AnalysisWho, what, when, where will the system be?

DesignHow will the system work?

ImplementationSystem delivery

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Identifying business valueLower costs / Increase profits

Analyze feasibilityDevelop work planStaff the projectControl and direct project

Planning

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Project Initiation

Planning

System Request

Feasibility Analysis

Approval Committee

Project Management

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Answer the Questions:Who will use the system?What will the system do?When will it be used?

Investigate the current systemIdentify possible improvementsDevelop a concept for new system

Analysis

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Analysis

Develops an Analysis Strategy which includes:

Analyze current system & its problemsInformation gathering

Interviews with users Input from project sponsor and requestor Leads to concept for new system

Process and Data modeling Models describe how business process will work

with the new system

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Analysis

Analysis+ System Concept

+ Models

are combined into theSystem Proposal

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Decides how the system will operateDesign strategy

Design internallyOutsource designBuy off the shelf

Architecture designHardware descriptionSoftware descriptionNetwork infrastructure

Design

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Design

Interface designHow users interact with systemForms / reports used by the system

Database and file SpecificationWhat data is to be storedWhat format the data will be inWhere the data will be stored

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Design

Program designWhat programs need to be writtenExactly what each program will do

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Design

These deliverables:Architecture designInterface designDatabase and file specificationProgram design

Form the System SpecificationThe System Spec is given to the programming team for implementation

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The system is actually built in this phaseUsually the longest phase

Implementation

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Implementation

ConstructionNew system is built and testedOften testing is the longest part

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Implementation

Conversion / InstallationOld system is turned offNew system is turned on

Three approachesCutover – immediate replacementParallel – both run for a whilePhased conversion – test group

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Implementation

Conversion includes development of a Training Plan

How to use new systemManage change due to new system

Support PlanPost implementation reviewsHow to identify changed needed for the system

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Processes and Deliverables

Process Product

Planning

Analysis

Design

Implementation

Project Plan

System Proposal

System Specification

New System and Maintenance

Plan

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SYSTEM DEVELOPMENT Methodologies

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What Is a Methodology?

A formalized approach or series of steps

A list of steps and deliverables

Writing code without a well-thought-out system request may work for small programs, but rarely works for large ones.

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Structured Design

Projects move methodically from one to the next stepGenerally, a step is finished before the next one begins

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Waterfall Development Method

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Pros and Cons of the Waterfall Method

Pros Cons

Identifies systems requirements long before programming begins

Design must be specified on paper before programming begins

Long time between system proposal and delivery of new system

Rework is very hard

Parallel Development

Addresses problem of time gap between proposal and deliveryBreaks project into parallel subprojectIntegrates them at the end

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Parallel Development

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Alternatives to the SDLC

Rapid Application Development (RAD)Phased DevelopmentPrototypingThrow-Away Prototyping

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Rapid Application Development

Critical elementsCASE toolsJAD sessionsFourth generation/visualization programming languagesCode generators

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RAD: Phased Development

Break overall system into a series of versionsEach version has Analysis, Design, and ImplementationOutput from on version is the input to the nextIncorporate ideas, issues, lessons learned in one version into the next version

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RAD: Phased Development

Pros Cons

Gets useful system to users quickly

Most important functions tested most

Initial system is intentionally incomplete

System requirements expand as users see versions

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RAD: Prototyping

Analysis, Design, Implementation are performed concurrentlyStart with a "quick-and-dirty" prototype

Provides minimal functionality

Repeat process, refining the prototype each timeStop when prototype is a working system

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RAD: Prototyping

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RAD: Prototyping

Pros Cons

Gets working system to users quickly

Fast paced. Hard to conduct careful, methodical analysis

Reassures users that the project is progressing

Quickly refines true requirements

Initial design decisions have long term staying power

Problems may come to light late in design, requiring re-design

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RAD: Throw-away prototyping

Use prototypes only to understand requirements

Example: use html to show UI

Prototype is not a working designOnce requirements are understood, the prototypes are thrown awayThe system is then built using SDLC

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Throwaway Prototyping

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Agile Development

Just a few rules that are easy to learn and followStreamline the SDLC

Eliminate much of the modeling and documentationEmphasize simple, iterative application development

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Agile Development

Examples include:Extreme Programming (XP)ScrumDynamic Systems Development Model (DSDM)

Extreme Programming

“Core Values”Communication – All to AllSimplicity - KISSFeedback – Embrace ChangeCourage – Quality First

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Extreme Programming

User StoriesCode small programUser FeedbackRepeatStandards are important

Naming conventionsCoding practices

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Selecting the Appropriate Methodology

Clarity of User RequirementsFamiliarity with TechnologySystem ComplexitySystem ReliabilityShort Time SchedulesSchedule Visibility

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Criteria for Selecting a Methodology

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Project Team Roles and Skills

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Information Systems Roles

Business analystSystem analystInfrastructure analystChange management analystProject manager

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Business Analyst

Focuses on business issues surrounding the system

The business value of the systemImprovements in business processesNew business processes needed with new system

Requires business skills and professional training (e.g. CPA)

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System Analyst

Focuses on IS issues How IS can improve business processesDesigns new information systemEnsures IS quality standards are maintained

Requires training & experience in design analysis, programming, business (to lesser degree)

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Infrastructure Analyst

Focuses on interfaces between new system & existing infrastructure

Makes sure new system follows organizational standardsIdentifies required infrastructure changes

Requires experience in network & DB administrationRequires knowledge of HW systems

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Change Management Analyst

Focuses on system installationDocumentation & support for usersCoordinate training of usersStrategies to overcome resistance

Requires experience in organizational behaviorRequires experience in change management

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Project Manager

Responsible for schedule and budgetEnsures promised benefits are deliveredManages team membersResponsible for project plan and reporting progressRequires project management experience

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Summary -- Part 1

The Systems Development Lifecycle consists of four stages: Planning, Analysis, Design, and ImplementationThe major development methodologies:

Structured design the waterfall method Parallel development

RAD development Prototyping (regular and throwaway)

Agile development XP streamline SDLC

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Summary -- Part 2There are five major team roles:

Business analystSystems analystInfrastructure analystChange management analystProject manager.