Agile Principles and Practices

The agile approach is to plan for what is known and to iterate against what is not known. Agile development thus focuses on building knowledge about value, cost and schedule and adjusting the plan to match reality.

Agile values

The Agile values are defined in the Agile Manifesto co-authored by 17 experts (Utah, April 11-13, 2001).

We are uncovering better ways of developing software by doing it and helping others do it.

Through this work we have come to value:

• Individuals and interactions over processes and tools
• Working software over comprehensive documentation
• Customer collaboration over contract negotiation
• Responding to change over following a plan

That is, while there is value in the items on the right, we value the items on the left more.

Agile principles

An Agile process should obey the following 12 principles:

1. Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
2. Welcome changing requirements, even late in development.
3. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
4. Business people and developers must work together daily throughout the project.
5. Build projects around motivated individuals.
6. The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
7. Working software is the primary measure of progress.
8. Agile processes promote sustainable development.
9. Continuous attention to technical excellence and good design enhances agility.
10. Simplicity — the art of maximizing the amount of work not done — is essential.
11. The best architectures, requirements, and designs emerge from self-organizing teams.
12. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.

Agile principles emphasize building working software that people can get hands on quickly, versus spending a lot of time writing specifications up front.

Agile practices

While Agile principles must be preserved during the project lifetime Agile practices must be adapted with changes.

A waterfall project carries many uncertain features forward to the testing phases just before shipping. An agile project eliminates the uncertainty in small iterations that include every part of development.

FIGURE 2.4 "Finding the fun", Agile Game Development.

Here are some thumb rules for a project:

• You break big problems down into smaller ones.
• You focus on the really important stuff and forget everything else.
• You make sure that what you are delivering works.
  → Do lots of testing, early and often.
• You go looking for feedback.
• You change course when necessary.
  → Change your project plan as things change.
• You become accountable.
  → Spend customer's money as if it were yours.

Agile planning

The master story list is prioritized by the customer and estimated by the development team. It forms the basis of your project plan and serves as a velocity tracker (how much can get done per iteration) and as a predictor (how much will get done in the future).

Adaptive planning is a cornerstone of agile delivery: when reality disagrees with your plan, you’ll change your plan.

Delivering a feature in Agile means doing everything necessary to produce shippable code (100% complete=analysis+design+coding+testing+more).

Agile teams

Agile teams adhere to rigid development practices such as good design, continuous refactoring to keep interfaces and code clean, automated and continuous integration of code, automated unit tests and integration tests.

• Agile teams must be able to self-organize.
• Business people and developers must work together daily throughout the project.
• Build projects around motivated individuals, give them the environment and support they need and trust them to get the job done. The best architectures, requirements and designs emerge from self-organizing teams.

• The business team decides what gets built.

  • It includes the product owner and the stakeholders (end users, marketing/sales, management)
  • The product owner is responsible for representing the customer and helping the team understand customers' requirements; he owns the product backlog and adjusts its contents and the associated priorities in response to changing business conditions.
• The Agile coach takes care of Agile practices.
• The development team decides how to build it.

Blurring roles, continuous development activities and team accountability are the main characteristics of an Agile team.

• There exist no narrowly defined roles like analyst, programmer, tester or documentation writer. Do privilege generalists when recruiting people for your team.
• Analysis, coding, design, testing and documenting are continuous and non-isolated activities.
• Optimally, a team should include up to seven people located in an open work area.
• Quality is a team responsibility.

About the Author

Stéphane Micheloud is a senior software engineer. He holds a Ph.D in computer science from EPFL and a M.Sc in computer science from ETHZ. At EPFL he worked on distributed programming and advanced compiler techniques and participated for over six years to the Scala project. Previously he was professor in computer science at HES-SO // Valais in Sierre, Switzerland.

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Other Articles

• Learning from the past (July 2009).
• Lean Framework (August 2009).
• XP Framework (August 2009).
• Scrum Framework (September 2009).
• Kaban Framework (September 2009).

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Last updated: July 25, 2009.

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