Software Development Models Overview

• Presents a comparative overview of different software development models.

Waterfall Model

• Approach: Sequential and linear.
• Phases: Fixed and sequential, following the order of requirements, design, implementation, testing, and deployment.
• Flexibility: Rigid, with changes being costly to implement.
• Risk Management: High risk due to potential late-stage issues.
• Customer Involvement: Minimal, primarily at the start of the project.
• Cost of Change: Very high, especially for late-stage alterations.
• Documentation: Extensive and detailed.
• Delivery Speed: Slow, with final delivery only at the end.
• Requirements: Fixed and well-defined from the outset.
• Client Involvement: Low, mainly at the beginning and end.
• Team Structure: Structured and hierarchical.
• Best For: Projects with well-defined and stable requirements.
• Cost & Time Efficiency: Can be expensive if changes are needed.
• Testing Approach: Performed after development.
• Examples:Suited for government, large enterprises, and safety-critical systems.

Spiral Model

• Approach: Risk-driven and iterative.
• Phases: Cyclical, involving planning, risk analysis, development, and evaluation.
• Flexibility: Moderate, allowing for midway adjustments.
• Risk Management: Strong, with risk analysis in each cycle.
• Customer Involvement: Moderate, at key milestones.
• Cost of Change: High due to risk assessments and iterations.
• Documentation: Moderate, focusing on key documents for risk analysis.
• Delivery Speed: Moderate, through prototypes and refinements.
• Requirements: Flexible, evolving with risk analysis.
• Client Involvement: Moderate, with feedback at key milestones.
• Team Structure: Structured, with a focus on risk.
• Best For: High-risk, complex, and large projects.
• Cost & Time Efficiency: Can be expensive due to risk analysis.
• Testing Approach: Continuous risk-driven testing.
• Examples: Typically used in aerospace, banking, and large-scale systems.

Incremental Model

• Approach: Build and refine software in increments.
• Phases: Multiple increments, each following a mini-waterfall approach.
• Flexibility: Flexible within increments.
• Risk Management: Moderate, with early delivery reducing risks.
• Customer Involvement: Moderate, with feedback after each increment.
• Cost of Change: Moderate, as changes can be managed within increments.
• Documentation: Moderate, with documents for each increment.
• Delivery Speed: Faster than waterfall, with partial system delivery in stages.
• Requirements: Can evolve between increments.
• Client Involvement: Moderate, with input at each increment.
• Team Structure: Flexible and cross-functional.
• Best For: Medium-sized projects with evolving requirements.
• Cost & Time Efficiency: Balanced cost and time.
• Testing Approach: Testing in each increment.
• Examples: Used in business software and medium-sized applications.

Agile (General)

• Approach: Iterative and adaptive.
• Phases: Continuous iterations involving plan, develop, test, and deploy.
• Flexibility: Highly flexible and adaptive.
• Risk Management: High, with continuous feedback reducing risks.
• Customer Involvement: High, with frequent feedback and collaboration.
• Cost of Change: Low, as frequent iterations reduce costs.
• Documentation: Minimal, focusing on working software over documentation.
• Delivery Speed: Very fast, with frequent releases and continuous delivery.
• Requirements: Highly dynamic, changing throughout development.
• Client Involvement: High, with continuous collaboration and feedback.
• Team Structure: Self-organizing teams.
• Best For: Dynamic projects with fast-changing requirements.
• Cost & Time Efficiency: Cost-effective for projects with changing needs.
• Testing Approach: Continuous testing and integration.
• Examples: Ideal for startups, web and mobile apps, and rapid development projects.

Agile - Scrum

• Approach: Time-boxed sprints.
• Phases: Sprint planning, development, sprint review, and retrospective.
• Flexibility: Moderate, within sprint boundaries.
• Risk Management: Medium, with sprint reviews helping manage risks.
• Customer Involvement: High, with the product owner engaging frequently.
• Cost of Change: Moderate, with changes only after the sprint ends.
• Documentation: Light documentation including the backlog.
• Delivery Speed: Fast, with each sprint delivering a working product.
• Requirements: Defined before each sprint.
• Client Involvement: High, with the product owner working closely with the team.
• Team Structure: Scrum team consisting of a product owner, scrum master, and developers.
• Best For: Teams working in fixed timeframes.
• Cost & Time Efficiency: Efficient for predictable work.
• Testing Approach: Testing occurs within each sprint.
• Examples: Used by software teams working in short iterations.

Agile - Kanban

• Approach: Continuous flow.
• Phases: Ongoing development with no fixed phases.
• Flexibility: High, allowing changes anytime.
• Risk Management: High, with constant adaptation.
• Customer Involvement: High, with stakeholders able to reprioritize anytime.
• Cost of Change: Low, allowing changes anytime.
• Documentation: Minimal, with just-in-time updates.
• Delivery Speed: Continuous, without fixed releases.
• Requirements: Prioritized continuously.
• Client Involvement: High, with stakeholders adjusting priorities anytime.
• Team Structure: No defined roles, with work assigned dynamically.
• Best For: Teams handling continuous workflows.
• Cost & Time Efficiency: Efficient for continuous, fast-paced work.
• Testing Approach: Testing is integrated into the workflow.
• Examples: Used in DevOps, IT support, and continuous product enhancements.