Agile software development
Agile software development is a group of software development methods based on iterative and incremental development, where requirements and solutions evolve through collaboration between self-organizing, cross-functional teams. It promotes adaptive planning, evolutionary development and delivery, a time-boxed iterative approach, and encourages rapid and flexible response to change. It is a conceptual framework that promotes foreseen interactions throughout the development cycle. The Agile Manifesto introduced the term in 2001.
|Software development process|
A software developer at work
|Activities and steps|
Incremental software development methods have been traced back to 1957. In 1974, a paper by E. A. Edmonds introduced an adaptive software development process. Concurrently and independently the same methods were developed and deployed by the New York Telephone Company's Systems Development Center under the direction of Dan Gielan. In the early 1970s, Tom Gilb started publishing the concepts of Evolutionary Project Management (EVO), which has evolved into Competitive Engineering. During the mid to late 1970s Gielan lectured extensively throughout the U.S. on this methodology, its practices, and its benefits.
So-called lightweight agile software development methods evolved in the mid-1990s as a reaction against the heavyweight waterfall-oriented methods, which were characterized by their critics as being heavily regulated, regimented, micromanaged and overly incremental approaches to development.
Proponents of lightweight agile methods contend that they are a return to development practices that were present early in the history of software development.
Early implementations of agile methods include Rational Unified Process (1994), Scrum (1995), Crystal Clear, Extreme Programming (1996), Adaptive Software Development, Feature Driven Development, and Dynamic Systems Development Method (DSDM) (1995). These are now collectively referred to as agile methodologies, after the Agile Manifesto was published in 2001.
Agile Manifesto 
In February 2001, 17 software developers met at the Snowbird, Utah, resort, 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.
The 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:
That is, while there is value in the items on the right, we value the items on the left more.
- Individuals and interactions over processes and tools
- Working software over comprehensive documentation
- Customer collaboration over contract negotiation
- Responding to change over following a plan
The meanings of the manifesto items on the left within the agile software development context are described below:
- Individuals and interactions – in agile development, self-organization and motivation are important, as are interactions like co-location and pair programming.
- Working software – working software will be more useful and welcome than just presenting documents to clients in meetings.
- Customer collaboration – requirements cannot be fully collected at the beginning of the software development cycle, therefore continuous customer or stakeholder involvement is very important.
- Responding to change – agile development is focused on quick responses to change and continuous development.
According to Kent Beck, the Agile Manifesto is based on twelve principles:
- 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 cooperation 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—the art of maximizing the amount of work not done—is essential
- 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.
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There are many specific agile development methods. Most promote development, teamwork, collaboration, and process adaptability throughout the life-cycle of the project.
Agile methods break tasks into small increments with minimal planning and do not directly involve long-term planning. Iterations are short time frames (timeboxes) that typically last from one to four weeks. Each iteration involves a cross functional team working in all functions: planning, requirements analysis, design, coding, unit testing, and acceptance testing. At the end of the iteration a working product is demonstrated to stakeholders. This minimizes overall risk and allows the project to adapt to changes quickly. An iteration might not add enough functionality to warrant a market release, but the goal is to have an available release (with minimal bugs) at the end of each iteration. Multiple iterations might be required to release a product or new features.
Team composition in an agile project is usually cross-functional and self-organizing, without consideration for any existing corporate hierarchy or the corporate roles of team members. Team members normally take responsibility for tasks that deliver the functionality an iteration requires. They decide individually how to meet an iteration's requirements.
Agile methods emphasize face-to-face communication over written documents when the team is all in the same location. Most agile teams work in a single open office (called a bullpen), which facilitates such communication. Team size is typically small (5-9 people) to simplify team communication and team collaboration. Larger development efforts can be delivered by multiple teams working toward a common goal or on different parts of an effort. This might require a coordination of priorities across teams. When a team works in different locations, they maintain daily contact through videoconferencing, voice chat, e-mail, etc.
No matter what development disciplines are required, each agile team will contain a customer representative. This person is appointed by stakeholders to act on their behalf and makes a personal commitment to being available for developers to answer mid-iteration questions. At the end of each iteration, stakeholders and the customer representative review progress and re-evaluate priorities with a view to optimizing the return on investment (ROI) and ensuring alignment with customer needs and company goals.
Most agile implementations use a routine and formal daily face-to-face communication among team members. This specifically includes the customer representative and any interested stakeholders as observers. In a brief session, team members report to each other what they did the previous day, what they intend to do today, and what their roadblocks are. This face-to-face communication exposes problems as they arise. "These meetings, sometimes referred as daily stand-ups or daily scrum meetings, are held at the same place and same time every day and should last no more than 15 minutes. Standing up usually enforces that rule."
Agile development emphasizes working software as the primary measure of progress. This, combined with the preference for face-to-face communication, produces less written documentation than other methods. The agile method encourages stakeholders to prioritize "wants" with other iteration outcomes, based exclusively on business value perceived at the beginning of the iteration (also known as value-driven).
Specific tools and techniques, such as continuous integration, automated or xUnit test, pair programming, test-driven development, design patterns, domain-driven design, code refactoring and other techniques are often used to improve quality and enhance project agility.
Light Agile Development (LAD) is a flavor of agile methodology that applies hand picked techniques from the wider range of agile practices to suit different companies, development teams, situations and environments. Another key aspect of LAD is that it tends to be user-centric, focusing primarily on the user experience and usable software interfaces and uses agile methodologies to deliver them. Most real-world implementations of Agile are really LAD in practice, since a core value of the method is flexibility, sensibility, and focus on getting stuff done.
In agile software development, an information radiator is a (normally large) physical display located prominenly in an office, where passers-by can see it. It presents an up-to-date summary of the status of a software project or other product. The name was coined by Alistair Cockburn, and described in his 2002 book Agile Software Development. A build light indicator may be used to inform a team about the current status of their project.
Comparison with other methods 
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Methods exist on a continuum from adaptive to predictive. Agile methods lie on the adaptive side of this continuum. Adaptive methods focus on adapting quickly to changing realities. When the needs of a project change, an adaptive team changes as well. An adaptive team will have difficulty describing exactly what will happen in the future. The further away a date is, the more vague an adaptive method will be about what will happen on that date. An adaptive team cannot report exactly what tasks they will do next week, but only which features they plan for next month. When asked about a release six months from now, an adaptive team might be able to report only the mission statement for the release, or a statement of expected value vs. cost.
The diagram below displays the differences between agile and waterfall development processes. By delivering working, tested, deployable software on an incremental basis, agile development delivers increased value, visibility, and adaptability much earlier in the life cycle, significantly reducing project risk.
Predictive methods, in contrast, focus on analysing and planning the future in detail and cater for known risks. In the extremes, a predictive team can report exactly what features and tasks are planned for the entire length of the development process. Predictive methods rely on effective early phase analysis and if this goes very wrong, the project may have difficulty changing direction. Predictive teams will often institute a change control board to ensure that only the most valuable changes are considered.
Formal methods, in contrast to adaptive and predictive methods, focus on computer science theory with a wide array of types of provers. A formal method attempts to prove the absence of errors with some level of determinism. Some formal methods are based on model checking and provide counter examples for code that cannot be proven. Agile teams may employ highly disciplined formal methods.
Agile methods have much in common with the Rapid Application Development techniques from the 1980/90s as espoused by James Martin and others. In addition to technology-focused methods, customer- and design-centered methods, such as Visualization-Driven Rapid Prototyping developed by Brian Willison, work to engage customers and end users to facilitate agile software development.
In 2008 the Software Engineering Institute (SEI) published the technical report "CMMI or Agile: Why Not Embrace Both" to make clear that Capability Maturity Model Integration and agile can co-exist. CMMI Version 1.3 includes tips for implementing Agile and CMMI.One of the differences between agile and waterfall is that testing of the software is conducted at different points during the software development lifecycle. In the waterfall model, there is a separate testing phase after implementation. In Agile XP, testing is done concurrently with implementation.
Agile methods 
Well-known agile software development methods include:
- Agile Modeling
- Agile Unified Process (AUP)
- Crystal Clear
- Crystal Methods
- Dynamic Systems Development Method (DSDM)
- Extreme Programming (XP)
- Feature Driven Development (FDD)
- Graphical System Design (GSD)
- Lean software development
- Velocity tracking
- Software Development Rhythms 
Method tailoring 
In the literature, different terms refer to the notion of method adaptation, including 'method tailoring', 'method fragment adaptation' and 'situational method engineering'. Method tailoring is defined as:
A process or capability in which human agents determine a system development approach for a specific project situation through responsive changes in, and dynamic interplays between contexts, intentions, and method fragments.
Potentially, almost all agile methods are suitable for method tailoring. Even the DSDM method is being used for this purpose and has been successfully tailored in a CMM context. Situation-appropriateness can be considered as a distinguishing characteristic between agile methods and traditional software development methods, with the latter being relatively much more rigid and prescriptive. The practical implication is that agile methods allow project teams to adapt working practices according to the needs of individual projects. Practices are concrete activities and products that are part of a method framework. At a more extreme level, the philosophy behind the method, consisting of a number of principles, could be adapted (Aydin, 2004).
Extreme Programming (XP) makes the need for method adaptation explicit. One of the fundamental ideas of XP is that no one process fits every project, but rather that practices should be tailored to the needs of individual projects. Partial adoption of XP practices, as suggested by Beck, has been reported on several occasions. Mehdi Mirakhorli proposes a tailoring practice that provides a sufficient road-map and guidelines for adapting all the practices. RDP Practice is designed for customizing XP. This practice, first proposed as a long research paper in the APSO workshop at the ICSE 2008 conference, is currently the only proposed and applicable method for customizing XP. Although it is specifically a solution for XP, this practice has the capability of extending to other methodologies. At first glance, this practice seems to be in the category of static method adaptation but experiences with RDP Practice says that it can be treated like dynamic method adaptation. The distinction between static method adaptation and dynamic method adaptation is subtle. The key assumption behind static method adaptation is that the project context is given at the start of a project and remains fixed during project execution. The result is a static definition of the project context. Given such a definition, route maps can be used to determine which structured method fragments should be used for that particular project, based on predefined sets of criteria. Dynamic method adaptation, in contrast, assumes that projects are situated in an emergent context. An emergent context implies that a project has to deal with emergent factors that affect relevant conditions but are not predictable. This also means that a project context is not fixed, but changing during project execution. In such a case prescriptive route maps are not appropriate. The practical implication of dynamic method adaptation is that project managers often have to modify structured fragments or even innovate new fragments, during the execution of a project (Aydin et al., 2005).
Software development life cycle 
The agile methods are focused on different aspects of the software development life cycle. Some focus on the practices (extreme programming, pragmatic programming, agile modeling), while others focus on managing the software projects (the scrum approach). Yet, there are approaches providing full coverage over the development life cycle (dynamic systems development method, or DSDM, and the IBM Rational Unified Process, or RUP), while most of them are suitable from the requirements specification phase on (feature-driven development, or FDD, for example). Thus, there is a clear difference between the various agile software development methods in this regard. Whereas DSDM and RUP do not need complementing approaches to support software development, the others do to a varying degree. DSDM can be used by anyone (although only DSDM members can offer DSDM products or services). RUP, then, is a commercially sold development environment (Abrahamsson, Salo, Rankainen, & Warsta, 2002).
Measuring agility 
While agility can be seen as a means to an end, a number of approaches have been proposed to quantify agility. Agility Index Measurements (AIM) score projects against a number of agility factors to achieve a total. The similarly named Agility Measurement Index, scores developments against five dimensions of a software project (duration, risk, novelty, effort, and interaction). Other techniques are based on measurable goals. Another study using fuzzy mathematics has suggested that project velocity can be used as a metric of agility. There are agile self-assessments to determine whether a team is using agile practices (Nokia test, Karlskrona test, 42 points test).
While such approaches have been proposed to measure agility, the practical application of such metrics is yet to be seen. There is agile software development ROI data available from the CSIAC ROI Dashboard.
Learn how agile you are with this Agility Calculator.
Experience and reception 
One of the early studies reporting gains in quality, productivity, and business satisfaction by using Agile methods was a survey conducted by Shine Technologies from November 2002 to January 2003. A similar survey conducted in 2006 by Scott Ambler, the Practice Leader for Agile Development with IBM Rational's Methods Group reported similar benefits. In a survey conducted by VersionOne (a provider of software for planning and tracking agile software development projects) in 2008, 55% of respondents answered that agile methods had been successful in 90-100% of cases. Others claim that agile development methods are still too young to require extensive academic proof of their success.
Some things that may negatively impact the success of an agile project are:
- Large-scale development efforts (>20 developers), though scaling strategies and evidence of some large projects have been described.
- Distributed development efforts (non-colocated teams). Strategies have been described in Bridging the Distance and Using an Agile Software Process with Offshore Development
- Forcing an agile process on a development team
- Mission-critical systems where failure is not an option at any cost (e.g. software for air traffic control).
The early successes, challenges and limitations encountered in the adoption of agile methods in a large organization have been documented.
In terms of outsourcing agile development, Michael Hackett, Sr. Vice President of LogiGear Corporation has stated that "the offshore team ... should have expertise, experience, good communication skills, inter-cultural understanding, trust and understanding between members and groups and with each other."
Agile methods have been extensively used for development of software products and some of them use certain characteristics of software, such as object technologies. However, these techniques can be applied to the development of non-software products, such as computers, motor vehicles, medical devices, food, and clothing; see Flexible product development.
Risk analysis can also be used to choose between adaptive (agile or value-driven) and predictive (plan-driven) methods. Barry Boehm and Richard Turner suggest that each side of the continuum has its own home ground, as follows:
|Agile home ground||Plan-driven home ground||Formal methods|
|Low criticality||High criticality||Extreme criticality|
|Senior developers||Junior developers||Senior developers|
|Requirements change often||Requirements do not change often||Limited requirements, limited features see Wirth's law|
|Small number of developers||Large number of developers||Requirements that can be modeled|
|Culture that responds to change||Culture that demands order||Extreme quality|
Agile methodologies can also be inefficient in large organizations and certain types of projects (see paragraph "Suitability"). Agile methods seem best for developmental and non-sequential projects. Many organizations believe that agile methodologies are too extreme and adopt a hybrid approach that mixes elements of agile and plan-driven approaches.
Agile has also been criticized by numerous observers as being a management fad. It exhibits many of the properties observed in past management fads including new jargon for existing processes, external consultants who specialize in its implementation and claims of a measurable business improvement via measurement of metrics defined by itself (e.g. velocity).
See also 
- Beck, Kent; et al. (2001). "Manifesto for Agile Software Development". Agile Alliance. Retrieved 14 June 2010.
- Gerald M. Weinberg, as quoted in Larman, Craig; Basili, Victor R. (June 2003). "Iterative and Incremental Development: A Brief History". Computer 36 (6): 47–56. doi:10.1109/MC.2003.1204375. ISSN 0018-9162. "We were doing incremental development as early as 1957, in Los Angeles, under the direction of Bernie Dimsdale at IBM's ServiceBureau Corporation. He was a colleague of John von Neumann, so perhaps he learned it there, or assumed it as totally natural. I do remember Herb Jacobs (primarily, though we all participated) developing a large simulation for Motorola, where the technique used was, as far as I can tell ... All of us, as far as I can remember, thought waterfalling of a huge project was rather stupid, or at least ignorant of the realities. I think what the waterfall description did for us was make us realize that we were doing something else, something unnamed except for 'software development.'"
- Edmonds, E. A. (1974). "A Process for the Development of Software for Nontechnical Users as an Adaptive System". General Systems 19: 215–18.
- http://www.gilb.com/Project-Management Evolutionary Project Management (EVO)
- Larman, Craig (2004). Agile and Iterative Development: A Manager's Guide. Addison-Wesley. p. 27. ISBN 978-0-13-111155-4
- 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, Stephen J. Mellor, Ken Schwaber, Jeff Sutherland, and Dave Thomas
- Ambler, S.W. "Examining the Agile Manifesto". Retrieved 6 April 2011.
- Beck, Kent; et al. (2001). "Principles behind the Agile Manifesto". Agile Alliance. Archived from the original on 14 June 2010. Retrieved 6 June 2010.
- Anderson, David (2005). "Declaration of Interdependence".
- Beck, Kent (1999). "Embracing Change with Extreme Programming". Computer 32 (10): 70–77. doi:10.1109/2.796139.
- Gauthier, Alexandre (17 August 2011). "What is scrum". Planbox.
- "Daily Stand-up Meeting". Planbox.
- Sliger, Michele; Broderick, Stacia (2008). The Software Project Manager's Bridge to Agility. Addison-Wesley. p. 46. ISBN 0-321-50275-2.
- Cockburn, Alistair. "Information radiator".
- Ambler, Scott (12 April 2002). Agile Modeling: Effective Practices for EXtreme Programming and the Unified Process. John Wiley & Sons. pp. 12, 164, 363. ISBN 978-0-471-20282-0.
- Boehm, B.; R. Turner (2004). Balancing Agility and Discipline: A Guide for the Perplexed. Boston, MA: Addison-Wesley. ISBN 0-321-18612-5. Appendix A, pages 165–194
- "Benefits of Agile Software Development". Agile 101. Retrieved 13 May 2013.
- Black, S. E.; Boca., P. P.; Bowen, J. P.; Gorman, J.; Hinchey, M. G. (September 2009). "Formal versus agile: Survival of the fittest". IEEE Computer 49 (9): 39–45.
- "TECHNICAL NOTE CMU/SEI-2008-TN-003 CMMI or Agile: Why Not Embrace Both".
- CMMI Product Team, ; CMMI for Development, Version 1.3 (CMU/SEI-2010-TR-033). Software Engineering Institute, Carnegie Mellon University, 2010. http://www.sei.cmu.edu/library/abstracts/reports/10tr033.cfm
- Ambler, S.W., (2012). Disciplined Agile Delivery (DAD): The Foundation for Scaling Agile Presentation Slide 15
- Lui, K.M., (2013). Software development rhythms: Searching for Simplicity Presentation Slide 15
- Aydin, M.N., Harmsen, F., Slooten, K. v., & Stagwee, R. A. (2004). An Agile Information Systems Development Method in use. Turk J Elec Engin, 12(2), 127-138
- Abrahamsson, P., Warsta, J., Siponen, M.T., & Ronkainen, J. (2003). New Directions on Agile Methods: A Comparative Analysis. Proceedings of ICSE'03, 244-254
- Abrahamsson, P., Salo, O., Ronkainen, J., & Warsta, J. (2002). Agile Software Development Methods: Review and Analysis. VTT Publications 478
- Aydin, M.N., Harmsen, F., Slooten van K., & Stegwee, R.A. (2005). On the Adaptation of An Agile Information(Suren) Systems Development Method. Journal of Database Management Special issue on Agile Analysis, Design, and Implementation, 16(4), 20-24
- "David Bock's Weblog : Weblog". Jroller.com. Retrieved 2 April 2010.
- "Agility measurement index". Doi.acm.org. Retrieved 2 April 2010.
- Peter Lappo; Henry C.T. Andrew. "Assessing Agility". Retrieved 6 June 2010.
- Kurian, Tisni (2006). Agility Metrics: A Quantitative Fuzzy Based Approach for Measuring Agility of a Software Process, ISAM-Proceedings of International Conference on Agile Manufacturing'06(ICAM-2006), Norfolk, U.S.
- Joe Little (2 December 2007). "Nokia test, A scrum-specific test". Agileconsortium.blogspot.com. Retrieved 6 June 2010.
- Mark Seuffert, Piratson Technologies, Sweden. "Karlskrona test, A generic agile adoption test". Piratson.se. Retrieved 6 June 2010.
- "How agile are you, a scrum-specific test". Agile-software-development.com. Retrieved 6 June 2010.
- CSIAC ROI Dashboard Retrieved 11 November 2011.
- "Agile Methodologies Survey Results" (PDF). Shine Technologies. January 2003. Retrieved 3 June 2010. "95% stated that there was either no effect or a cost reduction ... 93% stated that productivity was better or significantly better ... 88% stated that quality was better or significantly better ... 83% stated that business satisfaction was better or significantly better"
- Ambler, Scott (3 August 2006). "Survey Says: Agile Works in Practice". Dr. Dobb's. Retrieved 3 June 2010. "Only 6% indicated that their productivity was lowered ... No change in productivity was reported by 34% of respondents and 60% reported increased productivity ... 66% [responded] that the quality is higher ... 58% of organizations report improved satisfaction, whereas only 3% report reduced satisfaction."
- "The State of Agile Development" (PDF). VersionOne, Inc. 2008. Retrieved 3 July 2010. "Agile delivers"
- "Answering the "Where is the Proof That Agile Methods Work" Question". Agilemodeling.com. 19 January 2007. Retrieved 2 April 2010.
- Agile Processes Workshop II Managing Multiple Concurrent Agile Projects. Washington: OOPSLA 2002
- W. Scott Ambler (2006) Supersize Me in Dr. Dobb's Journal, 15 February 2006.
- Boehm, B.; R. Turner (2004). Balancing Agility and Discipline: A Guide for the Perplexed. Boston, MA: Addison-Wesley. pp. 55–57. ISBN 0-321-18612-5.
- Beck, K. (1999). Extreme Programming Explained: Embrace Change. Boston, MA: Addison-Wesley. ISBN 0-321-27865-8.
- K Petersen's doctoral research in Sweden Implementing Lean and Agile Software Development in Industry
- Schaaf, R.J. (2007). Agility XL Systems and Software Technology Conference 2007, Tampa, FL
- "Bridging the Distance". Sdmagazine.com. Retrieved 1 February 2011.
- Martin Fowler. "Using an Agile Software Process with Offshore Development". Martinfowler.com. Retrieved 6 June 2010.
- Art of Agile Development James Shore & Shane Warden pg 47.
- Evans, Ian. "Agile Delivery at British Telecom". Retrieved 21 February 2011.
-  LogiGear, PC World Viet Nam, Jan 2011
- Smith, Preston G (2007). Flexible Product Development. Jossey-Bass. p. 25. ISBN 978-0-7879-9584-3
- Barlow, Jordan B.; Justin Scott Giboney, Mark Jeffery Keith, David W. Wilson, Ryan M. Schuetzler, Paul Benjamin Lowry, Anthony Vance (2011). "Overview and Guidance on Agile Development in Large Organizations". Communications of the Association for Information Systems 29 (1): 25–44.
- "Kupe Kupersmith, "Agile is a Fad"".
- "Christopher R. Goldsbury, "The Agile Management Fad"".
- "Luke Halliwell, "The Agile Disease"".
Further reading 
- Annual State of Agile Development Survey: 2011 trends
- The Future of Agile Software Development
- Abrahamsson, P., Salo, O., Ronkainen, J., & Warsta, J. (2002). Agile Software Development Methods: Review and Analysis. VTT Publications 478.
- Augustine, Sanjiv & Bankston, Arlen. (2012). Story Mapping in a Nutshell. Managing Agile Projects.
- Cohen, D., Lindvall, M., & Costa, P. (2004). An introduction to agile methods. In Advances in Computers (pp. 1–66). New York: Elsevier Science.
- Dingsøyr, Torgeir, Dybå, Tore and Moe, Nils Brede (ed.): Agile Software Development: Current Research and Future Directions, Springer, Berlin Heidelberg, 2010.
- Fowler, Martin. Is Design Dead?. Appeared in Extreme Programming Explained, G. Succi and M. Marchesi, ed., Addison-Wesley, Boston. 2001.
- Larman, Craig and Basili, Victor R. Iterative and Incremental Development: A Brief History IEEE Computer, June 2003
- Riehle, Dirk. A Comparison of the Value Systems of Adaptive Software Development and Extreme Programming: How Methodologies May Learn From Each Other. Appeared in Extreme Programming Explained, G. Succi and M. Marchesi, ed., Addison-Wesley, Boston. 2001.
- Rother, Mike (2009). [[Toyota Kata]]. McGraw-Hill. ISBN 0-07-163523-8 Wikilink embedded in URL title (help)
- M. Stephens, D. Rosenberg. Extreme Programming Refactored: The Case Against XP. Apress L.P., Berkeley, California. 2003. (ISBN 1-59059-096-1)
- Shore, J., & Warden S. (2008). The Art of Agile Development. O'Reilly Media, Inc.
- Willison, Brian (2008). Iterative Milestone Engineering Model. New York, NY.
- Willison, Brian (2008). Visualization Driven Rapid Prototyping. Parsons Institute for Information Mapping.
- Wollmuth, Christine. "Risky Business". 2013
|Wikibooks has a book on the topic of: Software Engineering with an Agile Development Framework|
- Two Ways to Build a Pyramid, John Mayo-Smith (VP Of Technology At R/GA), October 22, 2001
- The New Methodology Martin Fowler's description of the background to agile methods
- Ten Authors of The Agile Manifesto Celebrate its Tenth Anniversary
- A look into the PMI-ACP (Agile Certified Practitioner)
- Agile Manifesto
- Agile Alliance