Explain comparative study between Waterfall, Prototype and Incremental model.
Comparative Analysis of Software Development Models​
| Aspect | Waterfall Model | Prototype Model | Incremental Model |
|---|---|---|---|
| Basic Approach | Linear and sequential | Iterative with emphasis on user feedback | Incremental delivery of functional products |
| Phases | Distinct, non-overlapping phases | Overlapping phases with repeated cycles | Repeated mini-waterfalls for each increment |
Requirements Handling​
Waterfall Model​
- All requirements must be known upfront
- Changes are difficult and expensive to accommodate
- Requirements document is comprehensive and detailed
- Little flexibility once requirements are approved
Prototype Model​
- Initial requirements may be unclear or incomplete
- Requirements evolve through feedback on prototypes
- Focus on discovering requirements through experimentation
- Highly flexible to changing requirements
Incremental Model​
- Core requirements must be well-defined initially
- Detailed requirements for later increments can evolve
- Requirements can be prioritized across increments
- Changes can be incorporated in future increments
User Involvement​
Waterfall Model​
- Limited to beginning (requirements) and end (testing)
- Minimal interaction during development phases
- Users see the product only after it's complete
- Feedback comes late in the development cycle
Prototype Model​
- Continuous involvement throughout development
- Regular feedback on working prototypes
- Active participation in shaping the final product
- Early and frequent interaction
Incremental Model​
- Periodic involvement at the end of each increment
- Feedback incorporated into subsequent increments
- Users can use completed increments while others are developed
- Moderate level of interaction
Risk Management​
Waterfall Model​
- High overall project risk
- Risks may not be discovered until late stages
- Little opportunity for risk mitigation during development
- All-or-nothing approach to success
Prototype Model​
- Early identification of technical and requirement risks
- Continuous risk assessment through prototype evaluation
- Allows experimentation to address uncertain areas
- Focused on reducing requirement and interface risks
Incremental Model​
- Divides risks across increments
- High-risk elements can be implemented early
- Individual increment failures are contained
- Progressive risk management throughout development
Development Time and Cost​
Waterfall Model​
- Predictable timeline and budget if requirements are stable
- Documentation overhead increases time and cost
- No early deliverables to offset costs
- Cost-effective for well-understood projects
Prototype Model​
- Unpredictable timeline due to iterative nature
- Multiple prototype revisions can increase cost
- Initial prototypes may be delivered quickly
- Higher cost due to potential rework
Incremental Model​
- First increment delivered relatively quickly
- Overall timeline may be longer than waterfall
- Progressive delivery provides return on investment
- Resource utilization can be optimized across increments
Testing and Quality Assurance​
Waterfall Model​
- Comprehensive testing phase after development
- Difficult to trace errors back to requirements
- Testing occurs late in the lifecycle
- Defects can be costly to fix
Prototype Model​
- Continuous testing throughout development
- Focus on functional testing of prototypes
- Emphasis on validating user requirements
- May lack rigorous testing if prototype becomes product
Incremental Model​
- Each increment is tested thoroughly
- Early increments receive more testing over time
- Integration testing occurs incrementally
- Defects can be addressed in subsequent increments
Documentation​
Waterfall Model​
- Comprehensive documentation at each phase
- Well-defined deliverables for each stage
- Documentation precedes development
- Formal documentation is a key deliverable
Prototype Model​
- Minimal documentation during prototyping
- Focus on working software over documentation
- Requirements often documented after implementation
- May lack complete system documentation
Incremental Model​
- Incremental documentation development
- Each increment has its own documentation
- Documentation evolves with the system
- Balanced approach to documentation
Suitability​
Waterfall Model​
- Small to medium projects with clear requirements
- Well-understood problem domains
- Stable requirements unlikely to change
- Projects requiring strict documentation for compliance
Prototype Model​
- Unclear or rapidly evolving requirements
- New technology or high user interface complexity
- Systems where user experience is critical
- Projects where requirements discovery is essential
Incremental Model​
- Large, complex systems
- Projects where early functionality delivery is valuable
- Systems that can be naturally divided into components
- Projects with prioritized requirements
By understanding these comparative aspects, organizations can select the most appropriate model based on project characteristics, requirements stability, user involvement needs, and risk tolerance levels.