Sunday, 30 August 2009

Iterative and Evolutionary development - Heads up

  • In this lifecycle approach, the development is organized into a series of short, fixed length mini projects called Iterations.
  • The resultant of each iteration is a subset of the actual production level software. Its neither a prototype nor an experimental throw away.
  • The software should grow with each iteration until it unifies with the expected end result and that's why its called Iterative and Incremental Development.
  • Its called Iterative and Evolutionary because feedbacks and adaptation evolves the specification and design.
  • Each iteration follows a model of Requirements analysis, followed by Design, followed by Implementation and test and finally complete system Integration test.
  • How changes are handled in such an iterative approach?
    • The only thing that's permanent is Change its inevitable, so there is no point confronting it - embrace change instead.
    • Having said that, the iterative development doesn't encourage or invoke sudden changes, it tries to ease the process of change.
    • The early iterations can help in getting quick feedback from the business user, developer and tester - this minimizes speculation, and helps reaping the actual requirements and validating the path of development.
    • Its easy to understand that work proceeds through a series of build-feedback-adapt cycles. The early iterations will no doubt, have some deviations from the actual requirements or the true path, but it will align itself to the true path later on.
  • There are multiple benefits of the Iterative Development:
    • Projects are less likely to fail.
    • Early rather than late mitigation of risks like technical, requirements, objectives, usability etc.,
    • Visible progress
    • Early feedbacks, user engagement, and adaptation leads to a refined and acceptable system
    • Complexity is managed - the team is saved from analysis-paralysis or very long and complex steps - they have portions in their plate that they can eat easily.
  • The length of an iteration is equally important - it doesn't make sense to have a 6-week iteration in a 2 month long project.
    • Short is good
    • Small steps, rapid feedback and adaptation are at the core of Iterative development.
    • A key idea is that whatever be the best length it has to be timeboxed - fixed. The partial system must be integrated, tested, and stabilized by the scheduled date - no exceptions at that.

No comments: