Agile is a software development methodology centered around flexibility and pragmatism in delivering a final product. This approach often necessitates a significant cultural shift within organizations, emphasizing the iterative delivery of software components rather than focusing solely on the complete application from the outset.
The advantages of Agile are numerous. It empowers teams to adapt to changing requirements, all while maintaining a strong focus on delivering tangible business value. Agile fosters a collaborative environment, enhancing efficiency across the organization as teams collaborate and understand their individual roles. Moreover, companies that embrace Agile software development can be confident in the quality of their products, thanks to continuous testing throughout the development lifecycle. This continuous feedback loop allows for timely adjustments and proactive identification of potential issues.
Agile has largely superseded the Waterfall model as the go-to development methodology. However, it now faces a potential challenge from the growing adoption of DevOps.
The Core Values of Agile: The Agile Manifesto
In 2001, a group of 17 software development professionals convened to discuss lightweight software development, resulting in the creation of the Agile Manifesto. This manifesto outlines the four core values of Agile, which continue to be central to the Agile movement despite ongoing discussions regarding their relevance in today’s landscape.
The four core values outlined in the Agile Manifesto are as follows:
- Individuals and interactions over processes and tools: Agile prioritizes the people driving the development process and their ability to respond to business needs. Valuing individuals above rigid processes and tools allows for greater flexibility and adaptability. When processes or tools dictate development, the team’s ability to adapt to change and meet customer needs diminishes.
- Working software over comprehensive documentation: Traditional software development involved extensive documentation throughout the development process. Agile streamlines this documentation to provide developers with the necessary information, such as user stories, without causing unnecessary delays. While documentation remains important, Agile emphasizes the creation of functional software.
- Customer collaboration over contract negotiation: Agile promotes continuous collaboration between the customer and project team rather than relying on formal contract negotiations. This collaborative approach ensures the customer is involved throughout the entire development process, enabling teams to better meet their needs. This can take the form of regular demos or even daily interaction with the development team.
- Responding to change over following a plan: Traditional software development often viewed change as an unwelcome expense. Agile embraces change, recognizing it as an opportunity for improvement and value creation. The short iterations within the Agile cycle allow teams to easily adapt to evolving requirements and adjust the development process accordingly.
The 12 Principles of Agile: Guiding the Development Process
The Agile Manifesto also outlines 12 core principles to guide the software development process:
- Prioritize customer satisfaction through early and continuous delivery of valuable software.
- Break down large tasks into smaller, manageable pieces that can be completed quickly.
- Recognize that the best results emerge from self-organizing teams.
- Provide motivated individuals with the resources and support they need, trusting them to complete the job effectively.
- Develop processes that promote sustainable development efforts.
- Maintain a consistent pace of completed work.
- Embrace changing requirements, even late in the project.
- Ensure daily collaboration between the project team and business stakeholders.
- Regularly reflect on how to improve team effectiveness and adjust behavior accordingly.
- Measure progress based on the amount of completed work.
- Strive for continuous excellence.
- Leverage change to gain a competitive advantage.
Agile development values emphasizing teamwork, flexibility, and customer focus.
These values and principles provide a framework for teams to approach the software development process.
The Agile Software Development Cycle: An Iterative Approach
The Agile software development cycle consists of six key stages:
- Concept
- Inception
- Iteration and Construction
- Release
- Production
- Retirement
Concept
The concept phase involves identifying potential business opportunities for each project and estimating the time and effort required for completion. This information informs project prioritization, helping organizations determine which projects are technically and economically feasible.
Inception
During inception, team members are identified, funding is secured, and initial requirements are discussed with the customer. This stage also includes creating a timeline that outlines team responsibilities and sets expectations for completing work within each sprint. A sprint represents a defined period during which specific tasks must be completed and prepared for review.
The Agile development cycle emphasizes continuous feedback and iterative improvement.
Iteration and Construction
Iteration and construction is the core of Agile development. Teams begin building working software based on requirements and continuous feedback. The Agile cycle relies on iterations, or individual development cycles, that build upon each other. Each iteration typically lasts two to four weeks, culminating in a working product ready for launch.
A typical iteration workflow includes:
- Defining requirements based on the product backlog, sprint backlog, and customer/stakeholder feedback.
- Developing software based on defined requirements.
- Conducting quality assurance testing, internal/external training, and documentation.
- Delivering and integrating the working product into production.
- Gathering feedback from customers and stakeholders to define requirements for the next sprint.
Release
The release phase involves final QA testing, bug fixes, finalization of system/user documentation, and deployment of the final iteration into production.
Production
Production focuses on ongoing support to maintain the software, ensuring smooth operation and user training. This phase continues until support ends or the product is retired.
Retirement
Retirement incorporates end-of-life activities, including customer notifications and final migration, culminating in the system’s removal from production. This typically occurs when a system is replaced, becomes outdated, or no longer aligns with the business model.
Throughout the Agile cycle, features can be added to the product backlog, but the process fundamentally involves repeating these steps iteratively until all items in the backlog are addressed. This iterative nature transforms the Agile cycle into more of a loop than a linear process.
Types of Agile Methodologies: Tailoring the Approach
The common goal of all Agile methodologies is to adapt to change and deliver working software efficiently. However, different methods vary in how they define the steps of software development. Common Agile methods include:
- Scrum
- Lean software development
- Extreme programming
- Crystal
- Kanban
- Dynamic systems development method
- Feature-driven development
Scrum
Scrum is a lightweight Agile framework used to manage iterative and incremental projects. In Scrum, the product owner creates a product backlog to collaborate with the team to identify and prioritize system functionality. The product backlog lists everything needed to deliver a successful software system, including bug fixes, features, and nonfunctional requirements. Once the product backlog is defined, only the team can add new functionality.
After prioritizing the backlog, cross-functional teams deliver working software increments during sprints, often within 30 days. After each sprint, the product backlog is reevaluated to select functions for the next sprint. Scrum’s popularity comes from its simplicity, productivity, transparency, and product owner involvement.
Lean Software Development
Lean software development focuses on value stream mapping to ensure the team delivers value to the customer. It’s a flexible, evolving method without rigid guidelines. The primary principles include:
- Increasing learning
- Empowering the team
- Fostering integrity
- Removing waste
- Understanding the whole
- Making decisions as late as possible
- Delivering the product as fast as possible
Lean relies on quick feedback between customers and programmers. To eliminate waste, users prioritize truly valuable features and deliver them in small batches. It also encourages automated unit tests alongside code and maximizes team productivity.
Extreme Programming
Extreme programming (XP) focuses on speed and continuous delivery. It promotes customer involvement, fast feedback loops, continuous planning and testing, and teamwork. Software is delivered frequently to improve software quality and responsiveness to changing requirements.
XP is based on communication, feedback, simplicity, and courage. Customers work with the development team to prioritize user stories, which the team delivers as tested, working software.
Crystal
Crystal is a lightweight, adaptable methodology that emphasizes people, interactions, business criticality, and system priority. Every project has unique characteristics requiring tailored policies, practices, and processes. Crystal uses process models like Crystal Orange, Crystal Clear, and Crystal Yellow, each with characteristics based on project priorities, team size, and system criticality.
Like other Agile methods, Crystal emphasizes frequent delivery of working software with customer involvement, adaptability, and eliminating bureaucracy. Key principles include communication, teamwork, and simplicity.
Kanban
Kanban uses a visual workflow management method to manage product creation and emphasize continuous delivery without added stress. It’s popular among teams practicing Lean.
Kanban’s basic principles include: visualizing the workflow; limiting the amount of work in progress; and improving work flow. Kanban helps teams work more efficiently, encouraging collaboration and defining the best workflow to promote continuous learning and improvement. While more flexible than Scrum, this flexibility can lead to ambiguity in estimating completion times.
Dynamic Systems Development Method
The dynamic systems development method responds to the need for a common framework for rapid software delivery. DSDM offers benefits such as holding business cases at its core, facilitating on-time delivery and incremental deliverables, and improved collaboration. Its eight key principles are:
- Collaboration
- On-time delivery
- Demonstrated control
- Continuous, clear communication
- A constant focus on the business need
- Iterative development
- Creation in increments from firm foundations
- Refusal to compromise quality
In DSDM, rework is built-in, and all changes must be reversible. System requirements are prioritized using the MoSCoW method, which ranks priority as follows:
- M: Must have
- S: Should have
- C: Could have, but not critical
- W: Won’t have now but could have later
Each iteration should include less critical items that can be removed so higher priority requirements aren’t affected.
Feature-Driven Development
Feature-driven development blends software engineering best practices, such as developing by feature, code ownership, and domain object modeling, to create a cohesive, model-driven process with short iterations. FDD begins by defining a model shape, which creates a feature list. The method then focuses on iterations that last two weeks and focuses on planning, designing, and building by feature. If a feature takes more than two weeks, it should be broken down. The primary advantage of FDD is that it’s scalable, since it uses the concept of “just enough design initially.”
Advantages and Disadvantages of Agile: A Balanced Perspective
The differences between Agile and Waterfall approaches have been compared over the years with Agile vs. Waterfall approaches.
During the Waterfall era, coders worked alone, with little input before handing off software to testers and production. Issues were either handled poorly or too late, causing delays or project cancellations.
The Agile model, with everyone involved and informed, represented a profound change in both company culture and the ability to get better software to market more quickly.
Collaboration and communication became as important as technology, and Agile has been adapted and modified to fit organizations of all sizes. This cultural shift also paved the way for DevOps.
With improved communication, collaboration, and transparency, mistakes are reduced, mid-course corrections are easier, and quality is improved.
Benefits of Agile methodology include:
- Improved communication and collaboration
- Adaptability
- Transparency
- Reduced risks
- Improved delivery and customer satisfaction
However, some argue the biggest disadvantage of Agile is its modification by many organizations. This widespread phenomenon is known as ScrumButs.
While Agile improves communication between developers and the business side, it’s been less successful bringing testing and operations into the mix, potentially contributing to the rise of DevOps.
Another concern is Agile’s lack of emphasis on technology, which can make it difficult to explain to upper management who don’t understand the role of culture in software development. Also, completing sprints on time can create a stressful work environment, potentially forcing overtime. Moreover, incremental delivery can result in fragmented output if team members get out of sync.
Finally, Agile methodologies might strain communication between developers and stakeholders due to different languages.
The disadvantages include:
- Over-customized processes
- Stressful time pressures
- Potential for project derailment
- Documentation often isn’t thorough
