Project Realization provides solutions and resources to support the management and development of software based products for the aerospace, automotive, and rail industries, including safety-critical systems.

Development Priorities: Agile v Traditional

Traditional Development

Priorities in Traditional Development

The traditional Waterfall model contains the following preconceptions:

  • All requirements are known before starting the development
  • Nothing will change during the development
  • Only start a phase of development after the previous phase is complete
  • Start testing the system after it has been developed
  • Only deliver the software once all the requirements have been completed

Consequently problems are discovered late, resulting in:

  • Significant rework
  • Significant impact on the schedule
  • Significant increase in costs
  • Reduced quality
  • Low confidence

The trade-off in a traditional development is that functionality always takes priority to cost and time.

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Agile Development

Priorities in Traditional Development

The Agile approach starts from quite a different position:

  • Appreciate that not all requirements are known at the start
  • Accept that things will change during development
  • Find the problems as soon as possible
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Mechanisms for Agile Development

  • Frequent delivery of a functioning ‘product’
  • Incremental introduction of functionality
  • Prioritise ‘product’ functionality to meet a Timebox
  • Start testing the ‘product’ as soon as possible

Consequently problems are discovered early and lessons learned, resulting in:

  • Reduced rework effort
  • Reduced impact on timescales
  • Increased confidence in the end product
  • Good quality
  • Continuous improvement

The trade-off in Agile is that not all functionality is known at the outset and therefore timescales and cost take precedence so that 'something' is always delivered.

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Process Comparison

Priorities in Traditional Development

A single diagram showing the two process priorities together.

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