Agile Methodology: Manifesto, Values & Principles

The Agile Manifesto (2001) was written by 17 software practitioners as a reaction to heavyweight, documentation-driven methodologies like Waterfall. It defines a set of values and 12 principles for iterative, customer-focused software development.

Four Agile Values

We 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

"While there is value in the items on the right, we value the items on the left more."

12 Agile Principles

• Customer satisfaction through early and continuous delivery of valuable software

• Welcome changing requirements, even late in development. Agile processes harness change for competitive advantage.

• Deliver working software frequently — weeks rather than months. Prefer shorter timescales.

• 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.

• The most efficient way to convey information is face-to-face conversation.

• Working software is the primary measure of progress.

• Agile processes promote sustainable development. Sponsors, developers, and users should maintain a constant pace indefinitely.

• Continuous attention to technical excellence and good design enhances agility.

• Simplicity — the art of maximizing the amount of work not done — is essential.

• The best architectures, requirements, and designs emerge from self-organizing teams.

• At regular intervals, the team reflects on how to become more effective and adjusts accordingly.

Agile vs Waterfall

Waterfall:                          Agile:
  Sequential phases                   Iterative cycles (sprints)
  Requirements frozen upfront         Requirements evolve
  Deliver at the end                  Deliver incrementally
  Change is a problem                 Change is expected
  Big design upfront                  Emergent design
  Works well when:                    Works well when:
    - Requirements are stable           - Requirements uncertain
    - Regulatory compliance             - Innovation / exploration
    - Physical systems                  - Most software products
    - Construction, manufacturing

Common Agile Misconceptions

• "No documentation" — Agile values working software OVER comprehensive docs, not zero docs. Write what adds value.

• "No planning" — Agile plans continuously at multiple horizons (sprint, release, quarter), just not all upfront.

• "No deadlines" — fixed-date releases are common. Agile adjusts scope to meet dates rather than extending dates.

• "Self-organizing means no management" — teams self-organize around the work, but still need leadership and facilitation.

• "Agile means fast with no quality" — XP practices (TDD, CI, pair programming) explicitly address quality.