Prototyping

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Prototyping

• By Michael McBee Shere Stewart

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Prototyping

• What is Prototyping?
• It is an iterative process involving analysts and
  users where a model of the proposed system is
  built then rebuilt according to user feedback.
• Why build a prototype?
• Visuals may enhance user feedback
• Reminder of requirements
• (ie. Bank Website)

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Prototyping process
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When Do You Prototype?

• WHEN DO YOU PROTOTYPE?
• BEFORE THE BEGINNING
• IN THE BEGINNING
• AFTER THE BEGINNING
• IN THE MIDDLE STAGES
• IN MIDDLE AND LATER STAGES
• IN THE LATER STAGES

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What are Prototypes used for?

• Learning. How well does it meet the customer
  needs?
• Communications. Help to visual the product or
  key components.
• Integration. Ensure that the components work
  together as planned.
• Milestones. Illustrate that the product has
  reached a certain level of functionality.

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When Prototyping Is Most Useful

• User Requirements are not clear
• Users and other stakeholders involved
• Complex designs require concrete specs
• Communication problems
• Tools available

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Drawbacks of Prototyping

• Informal documentation
• Idiosyncrasies with initial users
• Ignoring external integration

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Types of Prototyping

• Evolutionary
• Throwaway
• Paper

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Evolutionary prototyping

• Specification, design and implementation are
  inter-twined
• The system is developed as a series of increments
  that are delivered to the customer
• Techniques for rapid system development are used
  such as CASE tools and 4GLs
• User interfaces are usually developed using a GUI
  development toolkit

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Evolutionary
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Throw-away prototyping

• Discard prototype, build product from scratch
• Can use special prototyping technologies to
  build quick prototypes
• Dont have to design prototype carefully
• Coding can be more freestyle and unconstrained
• Need to redo all the work

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Throw-away prototyping
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Summary

• Clearly define the purposeWhy?
• What are you approximating (and not)?
• Determine the form of the prototype.
• Determine cost, construction plan.
• Test, gather data.