apid

1
evelopment
pplication
apid

• 3.3.1

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This presentation covers

• What Rapid Application Design is including
• Joint Development Application Workshops (JAD).
• Timeboxing
• The benefits and negatives of RAD.

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Introduction

• So far we have looked at the more common approach
  to system design and the prototyping method.
• Another method of software design is called Rapid
  Application Design.
• Like prototyping, the aim of RAD is to shorten
  the project duration.

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Rapid Application Design

• This model of system design must be completed
  within six months.
• It is considered that six months is the longest
  time that a users requirements will not change.
• The RAD approach is different to classic systems
  life cycles. It involves making a series of
  prototypes and getting feedback from the end user.

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Rapid Application Design

• With RAD the end-user is more involved throughout
  the design process.
• They evaluate each prototype. After each
  prototype is evaluated the designers will go back
  and make improvements to the prototype.
• This process is repeated until a final product is
  produced and agreed upon.
• After each round the process spirals closer to
  the final product. This is why this model is
  sometimes called the Spiral Model.

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Waterfall model with RAD
Feasibility Study
System Analysis
Prototype
Feedback
Feedback
Testing
Prototype
Prototype
Installation
Maintenance
Feedback
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Features of RAD

• RAD has two main features
• Joint Application Development workshops
• Timeboxing

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Joint Application Development (JAD)

• This method of system development has a greater
  emphasis on end-user involvement.
• Workshops are created in which the developers and
  the end-users meet to discuss requirements and
  assess design solutions.
• Through these workshops a greater understanding
  of what the system should do will be established.

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Joint Application Development (JAD)

• The aim is to establish an agreed set of
  requirements which should not change before the
  system has been implemented.
• Although the cost of these sessions are more
  expensive to run compared to analysis methods,
  the cost of miscommunication in terms of system
  requirements is far more costly.
• If the requirements are not communicated properly
  and a system has already been implemented the
  cost of changing the system would be a lot higher
  than spending more time at the start of the
  project establishing the requirements.

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Joint Application Development (JAD)

• For more information on JAD check out the article
  on Wikipedia which looks at what JAD is made up
  of.
• http//en.wikipedia.org/wiki/Joint_application_de
  sign
• There are loads of sites which provide
  information on JADresearch!

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Timeboxing

• Once the requirements have been established, they
  can be broken down into chunks.
• Each chunk of time will have a set of
  deliverables which must be met.
• If a deliverable is not met the chunk of time
  is not extended. Instead, the deliverable is
  moved into a new chunk of time.

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Timeboxing

• If deliverables overrun continually then the
  system as a whole may need to be reviewed.
• By doing this it prevents over-run deliverables
  piling up and causing big delays.

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Benefits of RAD

• RAD allows for continual evaluation of the
  product to take place.
• RAD ensures that requirements are understood
  fully before the system is implemented.
• The end-users are able to see what the end
  product would look like and how it would function
  before any of the functions are actually created.
• The system is usually created within six months
  (which is very quick in terms of system
  development).

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Negatives of RAD

• The end-users might get confused when they see a
  prototype that seems to work they may think
  that it wont take as long to create the system
  as what is projected.
• The system may work for the small number of
  people using the system, but when more users are
  added the system might not be able to cope.
• Time management is vital and is often very
  difficult to manage. If timescales start to slip
  then managing a project through RAD becomes less
  appropriate.

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What you need to be able to do

• Define the RAD methodology.
• Explain what the advantages and disadvantages are
  compared to other methodologies.
• Explain what JAD and timeboxing is.