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Friday, August 7, 2009

Agile Methodology

What Is Agile?

Agile methodology is an approach to project management, typically used in software development. It helps teams respond to the unpredictability of building software through incremental, iterative work cadences, known as sprints. But before discussing agile methodologies further, it’s best to first turn to the methodology that inspired it: waterfall, or traditional sequential development.
Where Did Agile Come From?

In 1970, Dr. Winston Royce presented a paper entitled “Managing the Development of Large Software Systems,” which outlined his ideas on sequential development. In essence, his presentation asserted that a project could be developed much like an automobile on an assembly line, in which each piece is added in sequential phases. This means that every phase of the project must be completed before the next phase can begin. Thus, developers first gather all of a project’s requirements, then complete all of its architecture and design, then write all of the code, and so on. There is little, if any, communication between the specialized groups that complete each phase of work.

It’s easy to see how this development agile methodology is far from optimized. First of all, it assumes that every requirement of the project can be identified before any design or coding occurs. Put another way, do you think you could tell a team of developers everything that needed to be in a piece of software before it was up and running? Or would it be easier to describe your vision to the team if you could react to functional software? Many software developers have learned the answer to that question the hard way: At the end of a project, a team might have built the software it was asked to build, but, in the time it took to create, business realities have changed so dramatically that the product is irrelevant. In that scenario, a company has spent time and money to create software that no one wants. Couldn’t it have been possible to ensure the end product would still be relevant before it was actually finished?

Why Agile?

Agile development methodology attempts to provide many opportunities to assess the direction of a project throughout the development lifecycle. This is achieved through regular cadences of work, known as sprints or iterations, at the end of which teams must present a shippable increment of work. Thus by focusing on the repetition of abbreviated work cycles as well as the functional product they yield, agile methodology could be described as “iterative” and “incremental.” In waterfall, development teams only have one chance to get each aspect of a project right. In an agile paradigm, every aspect of development — requirements, design, etc. — is continually revisited throughout the lifecycle. When a team stops and re-evaluates the direction of a project every two weeks, there’s always time to steer it in another direction.

The results of this “inspect-and-adapt” approach to development greatly reduce both development costs and time to market. Because teams can gather requirements at the same time they’re gathering requirements, the phenomenon known as “analysis paralysis” can’t really impede a team from making progress. And because a team’s work cycle is limited to two weeks, it gives stakeholders recurring opportunities to calibrate releases for success in the real world. In essence, it could be said that the agile development methodology helps companies build the right product. Instead of committing to market a piece of software that hasn’t even been written yet, agile empowers teams to optimize their release as it’s developed, to be as competitive as possible in the marketplace. In the end, a development agile methodology that preserves a product’s critical market relevance and ensures a team’s work doesn’t wind up on a shelf, never released, is an attractive option for stakeholders and developers alike.

Agile Methods

Some of the well-known agile software development methods:

* Agile Modeling
* Agile Unified Process (AUP)
* Agile Data Method
* DSDM
* Essential Unified Process (EssUP)
* Extreme programming (XP)
* Feature Driven Development (FDD)
* Getting Real
* Open Unified Process (OpenUP)
* Scrum
* Lean software development

Agile Practices

* Test Driven Development (TDD)
* Behavior Driven Development (BDD)
* Continuous Integration
* Pair Programming
* Planning poker

Regards,
~SA

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