Comparing Systems Development Methodologies

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Comparing Systems Development Methodologies

• K. Ingram 1998

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Evaluation for the situation

• is it the best for the situation?
• consider staff skills/cost of training
• availability of on-going support
• availability of automated support
• acceptibility to users and staff

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Methods of Comparison

• experiment - in controlled conditions -
  in the field
• survey
• feature analysis

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Difficulties of Comparison

• choosing similar projects for each method
• choosing similar staff for each method
• using the same project more than once changes the
  circumstances

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Feature Analysis

• Life Cycle coverage
• underlying philosophy
• degree of structure
• user role
• size of system for which it is useful
• techniques used
• use of CASE tools

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1. Life Cycle Coverage
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2. Philosophy - the approaches

• the Science approach the Hard approach -
  assumes concrete facts - uses top-down
  techniques
• the Systems approach the Soft approach -
  assumes user perceptions differ - assumes a
  build-up of mini-systems creates a difference
  whole system

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Philosophy
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3. Degree of Structure

• how rigidly the developers actions are
  prescribed

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4. User Role

• always included to some degree
• SSADM specifies that users must sign off products
  of each stage
• Yourdon does not formally prescribe user roles
  but recommends a good relationship

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5. System Size

• Small 1or 2 analysts over 6 months
• Large 5 analysts over 12months

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6. Techniques

• see attached sheet

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7. CASE

• does it support the method?
• does it support all stages of the method?
• does the method require a CASE tool?

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Common Features

• abstraction - conceptualising
• diagrammatic modeling techniques - data
  - processes - events
• user involvement

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DESMET

• Determining an Evaluation methodology for
  Software MEthods and Tools
• See DESMET