Incremental and Iterative Development
The simple ability to revisit the “phases” (Requirement collection, Analysis, Design, Development, Testing, Deply) of development dramatically improves project efficiency.
The idea of revisiting phases over and over is called “incremental and iterative development” (IID). The development lifecycle is cut up into increments or “iterations” and each iteration touches on each of the traditional “phases” of development. For example, with IID requirements is an ongoing process that is periodically revisited. As new requirements surface and as the scope changes, IID processes continually capture the requirements iteration after iteration Interestingly,
Agile project management approaches balance the four variables in software development while keeping in mind the limits associated with new product development. In software development there are four broad control factors. These factors are interconnected, when one changes at least one other factor must also change.
- Cost – or Effort. Available money impacts the amount of effort put into the system.
- Schedule – A software project is impacted as the timeline is changed.
- Requirements – The scope of the work that needs to be done can be increased or decreased to affect the project.
- Quality – Cut corners by reducing quality.
Because software development is often considered a sequential, linear process, middle and upper management often assumes that all four of these factors could be dictated to the development team under the waterfall approach. However software development cannot be described by a simple linear process because it cannot be predicted accurately in advance. It is therefore unreasonable to assume that management can control all four of these factors. In reality, management can pick values for three of the four factors at most, and the development process dictates the fourth.this expectation of full control unrealistic.
Lean Thinking
Another effective way to analyze how Agile methods increase efficiencies is to apply
lean manufacturing
Consider for example the “small batch” principle: things produced in smaller batches are of higher quality and efficiency because the feedback loop is short; controls can be adjusted more frequently, and resources are utilized efficiently to avoid “queuing” (see “queuing theory” and the theory of constraints).
Second, Agile methods encourage delaying irreversible decisions until the last responsible moment. Many software development organizations that implement Agile software development are finding they get something they never expected: options. Rather than locking into decisions at the beginning of a project, organizations can reduce risks by leaving options open to decide at a better time when more accurate information is available.
Third, the concept of frequent or continuous integration keep software development teams synchronized. Teams can work independently for a while but the code base never diverges for long periods of time, thereby reducing the risks associated with large integrations at the tail end of projects.principles to software development. The highly complex and uncertain nature of software development makes
Agile Requirements: A Focus on Business ROI
Agile projects avoid “up-front” requirements gathering for the reasons stated above:
customers cannot effectively produce all requirements in high enough detail for implementation to occur at the beginning of a project. Customers may not want to make decisions about the system until they have more information. Agile values a high visibility and customer involvement. The frequent demonstration and release of software common in Agile approaches gives customers a chance to “try software” periodically and provide feedback. Agile helps companies produce the “right product”. An iterative approach allows customers to delay decisions as well.
One of the biggest advantages to IID is that work can begin before all of the requirements are known. Many organizations are not fully staffed with business analysts cranking out reams of requirements specs.
IID is ideally suited then to take on bite-sized chunks of requirements that the customer can easily digest.
How do agile prioritize work?
This is largely because the unused features were specified in some upfront plan before the ratio of their cost to value was considered or even knowable. Focusing on high business value features first is therefore a critical component of efficient Agile development. Because we can change direction rapidly (every iteration) and the cost of change is low, there is a valuable opportunity for the customer to re-examine business factors at the
beginning of each iteration to select features for inclusion in the current iteration according to business ROI. Of course, the development team must bring technical risks to the customer, butin the end it is the customer that decides what the development team builds.
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