Agile methods are sometimes characterized as a force at the end of the spectrum from "plan-led" or "disciplined" methodologies. This distinction is misleading because it implies that agile methods "unplanned" or "include." Distinction is more accurate to say that there is uninterrupted from "adaptive" to "predictive". Agile methods are available on the "adaptive" side of the continuum.

Adaptive methods focus on adapting quickly to changing circumstances. If it is necessary to find a project-driven, adaptive changes in the team well. An adaptive team are finding it difficult to describe exactly what is happening in the future. Further to the date, the more adaptive method is vague about what happens on that date. An adaptive team can report exactly what tasks are being done in the next week, but only functions which are scheduled next month. When asked about the release after six months, when the adaptive team may only be able to understand the mission for the release of a statement or estimate of the cost compared to the cost.

Predictive methods, by contrast, focuses on planning for the future in detail. A predictive team can report exactly what features and functions are intended for overall development. Predictive teams have difficulty changing direction. The plan is typically optimized for the original destination and changing direction can cause completed work to be thrown away and done differently. Predictive teams are often the Institute for Change Control Board to ensure that only the most valuable change is taken into account.

Agile methods have much in common, that "Rapid Application Development technique has been embraced since the 1980s, James Martin and others (see RAD).

Contrast to the iterative development

Most agile methods share iterative Development's emphasis on building releasable software short period of time. Agile methods differ from iterative methods, that their period of time measured in weeks rather than months and work has been carried out in a very collaborative way. Most agile is also used to vary their time dealing with severely timebox.

Contrasted with the waterfall model

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Agile development is less common with the waterfall model. In some eyes, that the waterfall has been withdrawn, but since 2004 this model is still in common use. The waterfall model is the most predictive methods, the efficiency of the capture, analysis, design, coding and testing is a strict, pre-planned sequence. Success is generally measured objects deliverable requirements specifications, design documents, test plans, code reviews and the like. The waterfall model can lead to significant integration and testing efforts to end the cycle of time, usually ranging from several months to several years. The size and difficulty of the integration and testing effort is one of the reasons for project failure waterfall. Agile methods, by contrast, produce completely developed and tested features (but a very small subset of the whole) every few weeks or months. The emphasis is to get the lowest-functioning part of the value of options granted at an early stage, and continuously improving it / adding features throughout the project.

If the center of a large project can be canceled with a Waterfall project is often nothing to show it. Agile project has already provided a number of drops used in the code, which has been working in the live environment.

For each project, there is a risk of changing requirements. The longer and more complex the project, the greater the risk of this occurring. Waterfall projects that over the past year, there is a risk that is too slow to provide what is necessary, that the current market - things can change significantly at 12 months. A Waterfall project structure design often requires verbose document to define every aspect of the client / project sponsor requirements. Production design is a long process (months), and some of these efforts are wasted - the client wants something else, which during the year. Change control mechanisms are employed to absorb even more Management & developer time to act, adding overhead. changes are often seen as disruptive to the project, and thus to prevent! Agile approach is to acknowledge from the outset that we do not need to define everything as soon as we know now, it is unlikely that the more confident a year hence. Agile means that the client has a primary focus on the elements of the work of the supplies for the next 1-2 iterations. Each iteration's planning phase involves the client, giving them the opportunity to reprioritise their claims - and the new requirements, the outside world has already changed. [citation needed]

Some agile teams use the waterfall model, a small scale, repeating the entire waterfall cycle in every iteration. Other teams, in particular the Extreme Programming teams work activities at the same time.

Contrasted with "cowboy coding"

Cowboy coding is the absence of a defined method: team members do whatever they think is right. Agile Development, frequent reevaluation of plans, emphasis on face-to-face communication, and the relatively sparse use of documents sometimes causes people to confuse it with cowboy coding. Agile teams, however, defined by the (and often very disciplined and rigorous) processes, distinguishing between an agile approach to cowboy coding.

As with all methods, skills and experience of the user (s) to determine the success and / or abuse of such action. The more rigid and / or control of the checks and balances embedded within the process of systematically providing greater levels of responsibility for the user (s). This degradation is a well-planned, often defined as activities that lead to cowboy coding.


Suitability of agile methods


Although agile methods differ in their practice, they share several common characteristics, including iterative development, and focusing on interaction, communication and reduction of the intermediate objects. (Cohen et al., 2004) [5], the suitability of agile methods in general it is possible to examine a range of perspectives. From a product perspective, agile methods are suitable, if the requirements are emergent and rapidly changing, since they are less suitable for systems that have high criticality, reliability and safety requirements, although it is not complete consensus on this point (Cohen et al., 2004).  an organizational perspective, the suitability can be assessed by examining three key dimensions of organizational culture, people, and communications. In relation to these areas a number of key success factors have been identified (Cohen et al., 2004):

* Cultural Organization negotiations must be supported
* People must be entrusted 

* Fewer but more competent people
* Organizations must live with developers to make decisions
* Organizations must be in an environment that encourages rapid between team members

The most important factor is probably the size of the project (Cohen et al., 2004). As the size grows, face-to-face communication becomes more difficult. That is why agile methods are more suitable for smaller projects, teams with less than 20 to 40 people.

In order to determine the suitability of agile methods, more sophisticated analysis is necessary for an individual. The DSDM method, for example, gives the so-called fitness-filter "for this purpose. It is also the Crystal family of methods provides criteria on how to choose the method of the project. The selection is based on project size, importance and weight. But the other agile methods do not provide such a clear means to to assess their suitability for the project.

Some agile methods such as DSDM and Feature Driven Development (FDD), have argued that, in general, the pre-solutions, which means that they should be appropriate for each of agile software development project, taking into account the situational characteristics (Abrahamsonn et al., 2003).

Compared with the agile methods, it appears that they support the different phases of software development life cycle to different extents. This person may be typical of agile methods used in the candidate selection criteria for agile methods.

Agile development has been widely documented (see Experience Reports, below, as well as Beck  pg. 157, and Boehm and Turner  pg. 55-57) to the work of very small (<10 developers) co-operation in the teams. Agile development is expected to be particularly suitable for teams facing unpredictable or rapidly changing requirements. Although the teams have been reports of successful experience with agile development outside of those parameters, it is too little experience to present in April 2005 to draw firm conclusions.

Agile Development of the applicability of the following scenarios is an open question:

* Large-scale development efforts (> 20 developers). Scaling strategies are described. 
* Distributed development efforts (non co-located teams). Strategies are described in Bridging the Distance  and the use of Agile Offshore Software Development Process * Mission-and life-critical efforts
* Command-and-control company cultures


Boehm and Turner's risk-based approach


Barry Boehm and Richard Turner, a risk analysis is used to choose between the adaptive ( "agile") and predictive ( "plan initiated") methods.  the authors suggest that both sides of the continuum are in its home country:

Agile home ground:

* Low criticality
* Senior Developers
* Requirements change very often
* A small number of developers
* Culture thrives on chaos

Plan-driven home ground:

* High criticality
* Junior Developers
* Low requirements for change
* A large number of developers
* Culture, which requires that

Analysis of the project at home in these grounds, the risk of using an agile or plan-oriented method can be determined.


Adaptation of agile methods


A method should be flexible enough to allow for adjustments during project execution. There are three main issues related to the topic agile adaptation methods: the suitability of agile methods (and, in particular), tailoring the method, and finally, project management support.


Agile methods and method tailoring


If the literature, different terms to refer to the concept of adaptation of the method, including the method of tailoring "," method fragment adaptation 'and' situational method engineering. "Method tailoring is defined as follows:

Process or the ability of the people through their representatives to respond to the changes and the dynamic interplays between contexts, intentions, and the five fragments to determine the development of the system approach to the situation in a specific project. [12]

Potentially, almost all agile methods are suitable for method tailoring. Even the DSDM method is used for this purpose and have been successfully adapted to the context of the CMM., the appropriateness of the situation can be considered as a distinguishing characteristic between agile methods and traditional software development methods, the latter is relatively much more rigid and prescriptive. The practical effect of this is that agile methods allow project teams to adapt working practices according to the needs of individual projects. Activities are the specific activities and products which are part of the framework of the method. More broadly, the extreme level, the method of philosophy, which consists of several components, could be adapted (Aydin, 2004). 

In the case of XP, the adjustment method is the need to explicitly. One of the main ideas in XP is that it is not a process that is suitable for each project, as such, but rather the practice should be the needs of individual projects. There is also the experience of reports in which all the XP practices are adopted. Instead, the partial adoption of XP practices, as recommended by Beck (Kent Beck), has been reported repeatedly. 

A distinction can be made between static method adaptation and dynamic adaptation of the method. The key assumption behind static method adaptation is that the context of the project is given at the beginning of the project and will determine at the time of the execution of the project. The result is a static definition of the project context. Given such a definition, route maps can be used to determine which of the structured method fragments should be used for the specific project, which is based on the criteria in advance. Dynamic method adaptation, on the other hand, it is expected that the projects are located in the context of emerging. An emergent context implies that the project has to deal with the emergent factors that affect the conditions, but it is not predictable, and therefore have unforeseen. This also means that the project context is not fixed, but variable during the execution of the project. In such a case prescriptive route maps are not valid. The practical implication of dynamic method adaptation is that project managers often have to make a structured fragments or even innovate new fragments, during the execution of a project (Aydin et al, 2005).


Agile methods and project management


Agile methods differ greatly in how they cover the project management. Some additional guidelines for project management methods, but generally do not support. 
PRINCE2 is suitable for the proposed additional project management system.

History

The modern definition of agile software development evolved in response to the mid-1990s as part of "heavyweight" methods, which are characterized by a highly regulated, strictly on the use of micro-managed waterfall development model. Processes from the use of the waterfall model was considered to be bureaucratic, slow, demeaning, and objections to the way that software engineers actually work effectively.

A case can be made that agile and iterative development methods for the return to development practice seen early in the history of software development.

Initially, agile methods is called "easy methods." In 2001, prominent members of the Community met at snowbird and the name "agile methods." Later, some of these people were the Agile Alliance, a non-profit organization that promotes agile development.

Early agile methods created before 2000 contain scrummage (management) (1986), Crystal Clear, Extreme Programming (1996), Adaptive Software Development, Feature Driven Development, and DSDM (1995).

Extreme Programming, at the same time, if it was not the first agile method, inarguably established popularity of agile methods. Extreme Programming Kent Beck was established in 1996 as a way to rescue the struggling Chrysler Comprehensive Compensation (C3) project. Although this project was canceled at the end of the methodology was refined in XP Ron Jeffries' full-time coaching, public debate on Ward Cunningham's Portland Pattern Repository wiki, and to further the work of Beck, including a book in 1999. Extreme Programming is based on the elements seem crowded, and Ward Cunningham's Episodes pattern language.

Agile Methods

Some well-known agile software development methods:

* Extreme Programming (XP)
* Scrimmage
* Agile Modeling
* Adaptive Software Development (ASD)
* Crystal Clear and Other Crystal Methodology
* Dynamic Systems Development Method (DSDM)
* Feature Driven Development
* Lean Software
* Agile Unified Process (AUP)
* Dialogue with Development aka d3-DRIVEN

Other methods:

* Agile Documentation
* ICONIX
* Microsoft Solutions Framework (MSF)
* Agile Data Method
* Database refactoring

Examples of non-use of the principles of agile software practices:

* Lean manufacturing



Criticism


Agile development is sometimes criticized as cowboy coding. Extreme Programming's initial buzz and controversial tenets, such as the pair programming and continuous design, have attracted particular criticism, such as McBreen and Boehm and Turner.  However, much criticism was believed by Agile practitioners as the development of an agile misunderstandings.

In particular, Extreme Programming has been examined and criticisms Matt Stephens' Extreme Programming Refactored.

Criticisms include:

* An adequate structure and the necessary documents
* Supported only in the higher-level developers
* Incorporates software insufficient
* Too much cultural change to adopt
* It may be difficult contractual negotiations

Criticism with regard to inadequate software and lack of documentation concerning the Agile Modeling method, which can be easily adapted to the agile processes, such as the XP.