The Twelve Principles of Agile Software

• Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
• Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.
• Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
• 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 most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
• Working software is the primary measure of progress.
• Agile processes promote sustainable development. The sponsors, developers, and users should be able to 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, then tunes and adjusts its behavior accordingly.

Agile Manifesto

In February 2001, 17 software developers met at a ski resort in Snowbird, Utah, to discuss lightweight development methods. They published the "Manifesto for Agile Software Development" to define the approach now known as agile software development. Some of the manifesto's authors formed the Agile Alliance, a nonprofit organization that promotes software development according to the manifesto's principles.

Agile Manifesto reads, in its entirety, as follows:

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.

Twelve principles underlie the Agile Manifesto, including:

• Customer satisfaction by rapid delivery of useful software
• Welcome changing requirements, even late in development
• Working software is delivered frequently (weeks rather than months)
• Working software is the principal measure of progress
• Sustainable development, able to maintain a constant pace
• Close, daily co-operation between business people and developers
• Face-to-face conversation is the best form of communication (co-location)
• Projects are built around motivated individuals, who should be trusted
• Continuous attention to technical excellence and good design
• Simplicity
• Self-organizing teams
• Regular adaptation to changing circumstances

In 2005, a group headed by Alistair Cockburn and Jim Highsmith wrote an addendum of project management principles, the Declaration of Interdependence to guide software project management according to agile development methods.