Agile software development
There are many agile development methods; most minimize risk by developing software in short amounts of time. Software developed during one unit of time is referred to as an iteration, which may last from one to four weeks. Each iteration is an entire software project: including planning, requirements analysis, design, coding, testing, and documentation. An iteration may not add enough functionality to warrant releasing the product to market but the goal is to have an available release (without bugs) at the end of each iteration. At the end of each iteration, the team re-evaluates project priorities.
Agile methods emphasize face-to-face communication over written documents. Most agile teams are located in a single open office sometimes referred to as a bullpen. At a minimum, this includes programmers and their "customers" (customers define the product; they may be product managers, business analysts, or the clients). The office may include testers, interaction designers, technical writers, and managers.
Agile methods also emphasize working software as the primary measure of progress. Combined with the preference for face-to-face communication, agile methods produce very little written documentation relative to other methods. This has resulted in criticism of agile methods as being undisciplined.
Agile development is based on the Agile Manifesto. The Agile Manifesto is a statement of the principles that underpin agile software development. It was drafted 2001 where representatives of various new methodologies such as Extreme Programming, Scrum, DSDM, Adaptive Software Development, Crystal, Feature Driven Development, Pragmatic programming, met to discuss the need for lighter alternatives to the traditional heavyweight methodologies. The 17 signatories of the manifesto were: Kent Beck, Mike Beedle, Arie van Bennekum, Alistair Cockburn, Ward Cunningham, Martin Fowler, James Grenning, Jim Highsmith, Andrew Hunt, Ron Jeffries, Jon Kern, Brian Marick, Robert C. Martin, Steve Mellor, Ken Schwaber, Jeff Sutherland, Dave Thomas.
The philosophy of Agile development is implemented by different concrete methods like Extreme Programming or Scrum.