Various Approaches for Development of Information Systems

Definition:

When developing an Information System (IS), different approaches or methods can be followed depending on the project size, complexity, and user requirements.

Waterfall Model (Linear/Traditional Approach)

• The oldest and most widely used
• Phases are completed one after another, like a waterfall flowing down.

Phases in Detail:

1. Requirement Gathering: All system requirements are collected at the beginning.
2. System Design: Blueprint of the system architecture, interfaces, and data.
3. Implementation: Coding is done based on the design.
4. Testing: System is tested as a whole after development.
5. Deployment: System is delivered to users.
6. Maintenance: Fix issues after deployment.

 Diagram:

 Example:

Developing a railway ticket booking system with fixed scope and clear rules.

 Pros:

• Easy to manage
• Clear documentation
• Suitable for small projects

Cons:

• No flexibility after requirements are finalized
• Late testing phase may delay error detection

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 Prototyping Approach

• A working model of the system (prototype) is built to visualize and refine requirements before actual development.
• Iterative — built, tested, and improved repeatedly.

Types of Prototypes:

• Throwaway: Discarded after requirement clarity.
• Evolutionary: Improved until it becomes the final product.

Steps:

1. Gather initial requirements
2. Develop a prototype
3. Review by users
4. Revise prototype
5. Final system development

Diagram:

Example:

Developing a student portal with dashboards, feedback systems, and online tests.

Pros:

• High user involvement
• Reduces risk of failure
• Good for UI-focused applications

Cons:

• Time-consuming refinement cycles
• Scope may keep changing

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Spiral Model

• Combines features of the Waterfall and Prototyping
• Iterative development, with risk analysis at each phase.
• Each loop in the spiral represents one phase of the project.

Phases (Each Spiral Loop):

1. Planning
2. Risk Analysis
3. Engineering (Development)
4. Evaluation (Review & Feedback)

 Diagram:

Example:

Developing a banking system where security and performance risks are high.

Pros:

• Handles risk well
• Supports large, complex systems
• Flexible and iterative

Cons:

• Expensive
• Requires expert risk analysis

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Agile Approach

• Iterative and incremental.
• Delivers work in small cycles called sprints (1–4 weeks).
• Emphasizes collaboration, feedback, and working software over documentation.

Core Principles (Agile Manifesto):

• Individuals over processes
• Working software over documentation
• Customer collaboration over contract
• Responding to change over rigid planning

Popular Agile Frameworks:

• Scrum
• Kanban
• Extreme Programming (XP)

Diagram:

Example:

Developing a mobile app (e.g., food delivery or fitness tracker) with frequent updates.

Pros:

• Highly flexible
• Fast delivery
• Continuous improvement

Cons:

• Requires close coordination
• Can lack documentation
• Not suitable for fixed-scope projects

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Rapid Application Development (RAD)

• Focuses on speedy development using pre-built tools and reusable components.
• Encourages user feedback at every stage.

Phases:

1. Requirements Planning
2. User Design
3. Construction (Development)
4. Cutover (Implementation)

Diagram:

Example:

Developing a small HR system using a visual development tool (e.g., Zoho Creator, OutSystems).

Pros:

• Very fast development
• Encourages user interaction
• Reuse of components saves time

Cons:

• Limited for large or complex systems
• Requires skilled developers

 Comparison Table:

Final Tips for Choosing the Right Approach:

✅ Choose Waterfall if requirements are clear and fixed.

✅ Choose Prototyping if users need to see the system early.

✅ Choose Spiral if the project is complex and high-risk.

✅ Choose Agile if you need speed and flexibility with team collaboration.

✅ Choose RAD if you need a system fast with limited resources.

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