Iterative and Incremental Development

The practice of iterative and incremental development to structure the work on a project is common to all agile methods. In effect, iterative and incremental development when put collected becomes the primary enabler for most of the other agile techniques.

While iterative development is conjoint to all agile methods, the use of the technique does not essentially make a project agile. A number of additional techniques must be extant before a project can truly be considered agile. Some process-heavy methods, such as the full implementation of the Rational Unified Process (RUP) use iterations to establish the development work, yet they are too process-heavy to be considered agile.

Customer Involvement in Work Planning/Re-planning

One of the major basics of agile methods is the active participation of a "customer" in frequent, detailed work planning or re-planning at the start of each development iteration. What makes this so interesting, is that such close customer influence over the internal workings of the development team has been cited as a major cause of failed projects using traditional methods, but is also a major reason why agile methods are so successful. The kind of customer involvement is a double-edged sword — it can lead to a greater probability of meeting the customer's (developing) requirements, but can also lead to scope creep and increased the budgets if not managed well. Agile methods put structure to the management of this close customer involvement such that the likelihood of losing control of the development is minimal.

Concurrent Design/Engineering

Projects that are well-suited to agile methods are development projects where the requirements are either unclear or unstable, or where the design will continually change due to technical uncertainty. If the requirements and design are going to change frequently, then waiting for the "design phase" to end and getting a formal sign off from the project sponsor before proceeding with development will just lead to endless design churn. What is needed is the ability to start development on the portions where the design is reasonably complete, while still working on the design of other portions. In the engineering/construction world, this practice is called concurrent design or concurrent engineering. The main benefit here for agile projects, is that it gets the project moving into development mode quickly, and also allows the project still to be very responsive to changing requirements and designs.

Feature-Based Design/Planning/Reporting

All agile methods take a feature-based design approach. They may exhibit this approach differently, but underlying their techniques the base approach is still the same. Similarly, agile methods plan their projects around features, not tasks. Finally, agile methods all report progress on feature completion, not on task completion.

Continuous Building/Testing

All agile methods include the concept of continuous testing. Continuous testing allows you to find defects much earlier in the development cycle than waiting for them to emerge when testing is conducted at the very end. Earlier identification means more time to fix defects when it is convenient (most efficient) and more time to fix difficult bugs. Sometimes high-severity defects found late in the testing cycle of a traditional test-at-end method mean significant schedule delays. Continuous testing flushes these defects out earlier, minimizing their impact on the schedule.

To employ this type of testing on your project, you require three main pre-requisites:

ü  Iterative development,

ü  Frequent product builds