Information Systems Analysis

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Information Systems Analysis Development
Techniques a Comparison

• Techniques of Business
• Problem Solving

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What is systems analysis and design?

• Art?
• Science?
• Tools?
• Techniques/Procedures?
• Computer support in SDLC?

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What are business systems?

• Business systems have
• boundaries
• organizational objectives
• business functions
• integrated components (I, O, controls, people,
  etc.)

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Some concepts of a business system ..

• Decomposition as in manageable components (see
  Payroll)
• Modularity segments of approximately equal size
  (see input verification)
• Coupling (extent of integration)
• Cohesion (assignment of single function to each
  module)

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System Development Techniques

• Classical problem solving approach
• SDLC (a structured approach)
• Prototyping
• Applications Packages
• Dynamic Approach
• Joint Application Design(JAD)
• Participatory Design (PD)

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Classical vs. SDLC
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Classical vs.Prototyping (Rapid Application
Development)
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PROTOTYPING
problem definition feasibility requirements build/
use prototype refine evaluate expand a
ccept document final prototype post
implementation review
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Popularity of prototyping...

• Schulz Eierman report 34 use it,
• Necco et. al. report that 46 use it,
• Doke reports that 61 use it
• How is prototyping used?
• Replace various phases of SDLC,
• Replace the entire SDLC,
• SDLC should be applied to formalize prototyping,

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Popular Criticisms of SDLC (why prototyping is
popular?)

• Approach too sequential - discourage change
• Outputs from phases represented by documents
• user acceptance sought
• restrictive
• slow
• Observed poor user participation in early phases
• observed errors committed during early phases
• errors are costly to correct later

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Advantages of prototyping

• Advantages during analysis phase
• hard to define needs
• unknown needs
• Advantages during design
• quick alternatives evaluation
• Advantages during development
• prototype can be fielded (with cautions poor
  practice!)
• can be used to further define requirements
• User becomes a part of the process
• Can be used to test new ideas
• Disadvantages of prototyping?

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Classes of prototypes

• Slideshow (illustrative) prototype fronts
• Partial function prototype incomplete
• Simulation/pilot prototype for show only
• Evolutionary the real thing

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Importance of prototyping during SDLC (survey)

• 1. Problem definition/feasibility
• 2. Analysis requirements
• 3. Design of new system
• 4. Construction of new system
• 5. Implementation
• 6. Post-implementation review

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Support of SDLC phases with prototyping (survey)

• 1. Problem definition/feasibility
• 2. Analysis requirements
• 3. Design of new system
• 4. Development of new system
• 5. Implementation
• 6. Post-implementation review

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Replace SDLC with prototyping (survey)

• 1. Problem definition/feasibility
• 2. Analysis requirements
• 3. Design of new system
• 4. Development of new system
• 5. Implementation
• 6. Post-implementation review

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Classical approach Application packages
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DYNAMIC APPROACH

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More alternative approaches

• Joint Application Development (JAD)
• SA phase
• Requirements
• Design details
• Participatory Development (PD)
• May replace SDLC
• All of organization
• Mostly Scandinavia

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End System Development Overview