Agile software development is a group of software development values, principles and practices based on incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams.
Agile was developed in 2001 by a group of software development writers who got together to find common ground to promote better ways of developing software. This group included representatives from Extreme Programming, SCRUM, DSDM, Adaptive Software Development, Crystal, Feature-Driven Development, Pragmatic Programming, and others sympathetic to the need for an alternative to documentation driven, heavyweight software development processes.
What emerged from this discussion was an agreement on a common set of values and principles that underlay the new approaches to lightweight software development. This was the Manifesto for Agile Software Development which says:
“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.”
It’s important to note that Agile does not advocate abandoning the values on the right. These values do help you develop software it’s just that they have been overemphasized by most organizations.
“We follow these principles:
- Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.
- We welcome changing requirements, even late in development. Agile processes harness change for the customer’s competitive advantage.
- We 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.
- We 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.”
Many people think Agile is just a set of useful processes and tools. This is not the case. Agile is a set of common values and principles that the processes and tools have in common.
The practices themselves are evolving over time and new Agile practices such as Kanban are emerging. These practices should not be implemented rigidly because they are only a means to an end. You can and should select the practices you need and tailor them for your situation. As long as you’re sticking to the core values and principles you are still being Agile.
Conceptually Agile is a subset of Lean principles and practices which are in turn a subset of Systems Thinking.
For example the founders of Scrum acknowledge that Scrum was inspired by Lean Product Development practiced by Japanese companies such as Fuji-Xerox, Canon, Honda and NEC in the 70’s and 80’s. In the past few years this has been fully developed in Lean Software Development. Lean in turn is about seeing the whole system and understanding its assumptions and feedback loops which is explored more fully in Systems Thinking.
To help you learn more about Agile I have listed what I think are the classic texts on the field by subject. Start reading and try it out for yourself.
Agile Reading List
Kanban: Successful Evolutionary Change for Your Technology Business by David J. Anderson and Donald G Reinertsen
Agile Project Management: Creating Innovative Products (2nd Edition) by Jim Highsmith
The Rational Unified Process Made Easy: A Practitioner’s Guide to the RUP: A Practitioner’s Guide to the RUP by Per Kroll, Philippe Kruchten and Grady Booch
DSDM: Dynamic Systems Development Method: The Method in Practice by Jennifer Stapleton and Peter Constable
Lean-Agile Software Development: Achieving Enterprise Agility by Alan Shalloway, Guy Beaver and James R. Trott (Nov 1, 2009)
Agile Business Analysis
Refactoring: Improving the Design of Existing Code by Martin Fowler, Kent Beck, John Brant and William Opdyke
The Pragmatic Programmer: From Journeyman to Master by Andrew Hunt and David Thomas
Fit for Developing Software: Framework for Integrated Tests by Rick Mugridge and Ward Cunningham
Continuous Integration: Improving Software Quality and Reducing Risk by Paul M. Duvall, Steve Matyas and Andrew Glover