Agile software development – also known as Agile – is a type of software development methodology. The methodology of Agile software development is centred around adaptive planning, self-organisation, flexibility and short delivery times. It has a people and results-focused approach which effectively works in accordance with our rapidly changing world.

The Agile model applies a level of pragmatism to the delivery of the finished product. It primarily focuses on the clean delivery of individual pieces or parts of the software rather than on the entire application.

How does the Agile software development cycle work?

The Agile software development cycle is based on six major steps –concept, inception, iteration/construction, release, production and retirement.

Step 1 – Concept

The first step in the process of the agile software development cycle is concept. This stage involves the identification of business opportunities in each potential project and estimates the time and work that will be needed to complete the project. 

This information allows for prioritising and discerning projects i.e. which ones are worth pursuing in terms of technical and economic feasibility. 

Step 2 – Inception 

In this step, the team members are identified and funding is established. The initial requirements are discussed with the customer and a timeline is created to determine the expected delivery.

The timeline allows the team to outline the various responsibilities a member is expected to perform. It also defines the period by which the work is expected to be completed for each sprint, i.e. the set period of time within which the specific work has to be completed and to be presented for review.

Step 3 – Iteration/Construction –

The third step begins when the team begins to develop the software based on requirements and continuous feedback. The methodology of the Agile software development cycle depends on iterations i.e. on single development cycles. These single development cycles are co-dependent and lead to the next step of the overall project development and completion.

Each iteration, with a set date of completion, lasts typically between two to four weeks. The motive is to have by the end of each iteration a complete working product to launch.

There are multiple iterations throughout the development cycle where each iteration has its own workflow.

A typical iteration flow has –

• well-defined requirements based on the product backlog, sprint backlog and customer and stakeholder feedback;

• developing software as per set requirements;

• quality assurance tests, along with internal and external training and documentation;

• production of the working product by delivering and integrating them;

• defining new requirements for the next sprint of the iteration by assembling customer and stakeholder feedback

Step 4 – Release –

At this step, the final quality tests are conducted. Before the final iteration is released into production, it is further tested for any remaining defects, then the system is finalized according to the user documentation.

Step 5 – Production –

The fifth step of production ensures proper maintenance of the software by focusing on and offering the necessary support required.

Here the development team is accountable for smoothly running software while teaching users how to use it. This stage of production is continued until the support has ended or the product is further planned for retirement.

Step 6 – Retirement –

The final step of retirement incorporates all end-of-life activities. Here the system is released from production. It is usually done when a system is to be replaced with a new release or if it becomes obsolete, redundant, or begins to go against the business model

Different features can be added to the product backlog of the Agile cycle, however, the overall process must repeat each step over and over until every item in the backlog has been satisfied.

This makes the process of software development in the Agile cycle a loop rather than a linear process. An enterprise may at any given period of time work simultaneously on multiple projects with iterations. Where these iterations are logged on different product lines with a variety of internal and external customers offering different business needs. Thus, the Agile software development cycle works in accordance with swiftly changing variables while balancing a fine line between too much process and just enough.

Agile Methodologies – An overview 

Agile significantly abandons the risk of spending an incomprehensible amount of time on a process that possesses the chance of failure due to a small error in an early phase.

Instead, it relies on a well-built team working directly with customers to understand and accomplish the goals and continue to offer solutions in a quick incremental way.

Here have a quick read of the 5 advantages of Agile software development methodology –

Quick and compact –

Traditional software development involved a number of phases such as outlining the requirements, planning, designing, building, testing, and delivery. Unlike this, the Agile methodology is quick and deploys the first increment in a couple of weeks followed by the entire piece of software in a couple of months.

Collaboration and Communication –

Agile teams work together at every phase of the project through face-to-face meetings. This enhances the scope of collaboration and communication. Because it ensures that the process and work stay on track even if the circumstances or conditions change.

Regular Feedbacks – 

In the Agile methodology, each phase tracks the success and the speed of the development of the process. Thus, it offers very transparent and systematic feedback helping the software development function.

Trust and Credibility –

Agile teams and employees work with self-confidence. Rather than following a set of predetermined rigid rules, they understand the task and create a framework of their own. This improves the work pattern and makes the process more trustworthy and credible. Hence, it helps in improving customer satisfaction.

Adjustability –

As the teams work directly with the customers, they form their own timelines and set their own goals. This allows them to practice and work with a spirit of adjustability and flexibility.

The 12 principles of Agile –

The characteristics of agile software development depend on these 12 core principles –

1. Satisfy customers with early and continuous delivery of valuable work.

2. Break big work into smaller tasks that can be completed quickly.

3. Recognise that the best work results from self-organised teams.

4. Provide motivated individuals with a supporting and trusting environment for the completion of work.

5. Create processes that promote sustainable efforts.

6. Maintain a regular pace for completed work.

7. Welcome the changing requirements, even at the later part of projects.

8. Assemble the project teams and business owners on a regular basis throughout the project.

9. Have the team reflect at uniform intervals to enhance effectiveness and then tune and adjust their behaviour accordingly.

10. Measure progress by the amount of work completed.

11. Harness change for a competitive advantage.

12. Continually seek excellence.

Examples of Agile methodologies –

Every Agile methodology aims to embrace and adapt to change while delivering working software as efficiently as possible. However, each method differs from others in a way of defining the steps of software development.

The most popular Agile methods include used are –

Scrum – 

Scrum is the most popular Agile framework. Over the years, Scrum has gained popularity due to its simplicity and productivity. 

Being a lightweight framework it is used by project managers to control all types of iterative and incremental projects. A product backlog is created by the owner allowing them to work as a team while identifying and prioritising system functionality.

This backlog includes everything that is to be accomplished to deliver a successful, working software system – including functions such as fixing bugs, features and non-functional requirements. Once the product backlog is defined, no further additions are made to the functionality, except those by the corresponding team.

As the priorities are set by the team and the product owners, cross-functional teams begin their work and ascertain the time to deliver working increments of software during each sprint (i.e. mostly within 30 days). In order to select a new set of deliverable functions for the next sprint, the product is further re-evaluated, analysed and reprioritised after each sprint.

Lean Software Development –

 Lean Software Development is yet another iterative method. This method focuses on using value stream mapping to ensure that the team effectively delivers value to the customers. Lean software development follows these flexible primary principles –

1. Increasing learning

2. Empowering the team

3. Fostering integrity

4. Removing waste

5. Understanding the whole

6. Making decisions as late as possible

7. Delivering the product as fast as possible

To provide fast and efficient development workflows, the lean method relies on fast and reliable feedback between the customers and programmers. It provides individuals and small teams with decision-making authority rather than relying on a hierarchical flow of control. The lean method eliminates waste as it asks the users only to select only truly valuable features for their system. Prioritising these chosen features, these features are delivered in small batches.

Extreme Programming (XP) method – 

The XP method is a disciplined approach and focuses on speedy and continuous delivery. It encourages customer involvement, thus promoting faster feedback loops, continuous planning, testing and close teamwork.

The XP method works closely with customers and is based on the values of communication, feedback, simplicity and courage. Its main goal is to improve software quality and responsiveness when met with changing customer requirements. To maximise productivity, the XP method provides users with a supportive, lightweight framework. It guides and helps them to ensure high-quality enterprise software.

Crystal – 

Crystal is a lightweight and adaptable methodology, that focuses on people and interactions while working on an Agile project. This methodology of Agile software development works on the realisation that every project possesses unique characteristics. Thus, each Agile Project requires a slightly tailored set of policies, practices and processes for development.

It is made up of a collection of Agile process models, such as Crystal Orange, Crystal Clear and Crystal Yellow, where each model possesses its own unique characteristics. These characteristics are driven by different factors, including project priorities, team size and system criticality.

Alike other Agile methodologies, Crystal also encourages high customer involvement, adaptability and the elimination of bureaucracy and distractions. The key principles of Crystal include communication, teamwork and simplicity.

Kanban –

Kanban is a highly visual workflow management method. Kanban emphasises continuous delivery while allowing teams to actively manage product creation. It is popular among the Lean software development practising teams and encourages continuous collaboration. 

Kanban works on three basic principles i.e. visualising the workflow; limiting the amount of work in progress; and improving the flow of work. 

Dynamic Stress Development Method (DSDM) – 

There are eight key principles of the DSDM methodology of Agile software development –

1. Collaboration

2. On-time delivery

3. Demonstrated control

4. Continuous, clear communication

5. A constant focus on the business need

6. Iterative development

7. Creation in increments from firm foundations

8. Refusal to compromise quality

Failure to meet one principle introduces risk to the successful completion of the project.

Thus, in this method, rework is built into the process and all changes must be reversible. The DSDM methodology incorporates the MoSCoW rules, and prioritises the works as –

M – must have

S – should have

C – could have, but not critical

W – won't have now, but could have later

Each iteration should have the less critical item so that one can be removed so higher priority requirements are not impacted.

Feature-Driven Development (FDD) –

The FDD method creates a cohesive, model-driven, short-iteration process by blending best software engineering practices such as developing by feature, code ownership and domain object modelling. The FDD method begins by defining an overall model shape and thus in turn creates a feature list. It then further proceeds with iterations that last two weeks and focus on planning, designing and building by feature. 

In case it takes more than two weeks to build a feature takes, then it should be broken down into smaller features.