Agile Model in Software Engineering
- The word “Agile” means swift and adaptable. The Agile process model is a software development approach based on iterative and incremental development. Unlike traditional models, Agile breaks the project into smaller, manageable iterations instead of relying on long-term planning.
- Each iteration typically lasts 1 to 4 weeks, during which a cross-functional team completes all development phases—from planning and design to coding and testing. After every iteration, a working product is demonstrated to the client, reducing delivery time and minimizing risks.
Phases of the Agile Model
The Agile software development process consists of six main phases:
Requirements Gathering
- Identify business opportunities and project feasibility (technical and economic).
- Define what needs to be built and estimate the required time and effort.
Design the Requirements
- Collaborate with stakeholders to define system requirements using tools like user flows or UML diagrams.
Construction / Iteration
- Developers and designers build a minimum viable product (MVP) with basic functionality, to be improved in future iterations.
Testing / Quality Assurance
- The QA team tests the product for bugs and verifies performance.
Deployment
- Release the product into the user’s environment for real-world use.
Feedback
- Collect user feedback and incorporate changes in the next iteration.
Agile Testing Methods
Agile emphasizes functional software, adaptability, and collaboration. Several methodologies implement these principles in different ways:
1. Scrum
A framework focused on team management and task tracking during development.
- Scrum Master: Facilitates the process, manages obstacles.
- Product Owner: Creates and prioritizes the product backlog.
- Scrum Team: Self-manages and completes work in sprints.
2. eXtreme Programming (XP)
- Focuses on continuous delivery, frequent releases (every 1–3 weeks), customer collaboration, and test-driven development. Core values include simplicity, communication, feedback, and courage.
3. Crystal
Prioritizes team communication and adaptability.
Key phases:
- Chartering: Team building, planning, and feasibility.
- Cyclic Delivery: Updates release plans and delivers working software.
- Wrap-Up: Deployment and post-deployment adjustments.
4. Dynamic Systems Development Method (DSDM)
A rapid application development (RAD) framework focused on active user involvement and team decision-making.
Key techniques:
- Timeboxing
- MoSCoW prioritization
- Prototyping
5. Feature Driven Development (FDD)
- Emphasizes design and development by feature, breaking work into functional components developed and delivered individually.
6. Lean Software Development
Inspired by lean manufacturing, it aims to increase speed and reduce cost through principles like:
- Eliminate Waste
- Amplify Learning
- Early Delivery
- Empower the Team
- Build Integrity
- Optimize the Whole
- Defer Commitment
The 12 Agile Principles
Outlined in the Agile Manifesto, these principles guide Agile development:
- Satisfy customers through early and continuous delivery.
- Welcome changing requirements, even late in development.
- Deliver working software frequently.
- Collaborate daily between business and tech teams.
- Build projects around motivated individuals.
- Use face-to-face conversation as the best form of communication.
- Measure progress through working software.
- Promote sustainable development.
- Maintain a constant pace.
- Focus on technical excellence and good design.
- Keep it simple.
- Reflect regularly and adjust for better effectiveness.
When to Use the Agile Model
Agile is ideal when:
- Frequent changes are expected.
- A skilled and collaborative team is available.
- Continuous customer involvement is possible.
- The project is small to medium-sized.
Advantages of Agile
- Faster and continuous delivery
- Real-time client collaboration
- High flexibility and adaptability
- Better risk management
- Reduced development time
Disadvantages of Agile
- Lack of detailed documentation
- Difficult for new teams or inexperienced developers
- Maintenance challenges post-project
- Not ideal for projects with rigid regulatory requirements
Traditional vs. Agile SDLC Models
Use Cases of Agile Model
- Software Development: Rapid delivery of working modules.
- Project Management: Promotes adaptability and collaboration.
- Product Development: Incorporates feedback for continuous improvement.
- Marketing: Iterative campaign testing and optimization.
- Dynamic Environments: Where change and stakeholder input are constant.
