Iterative development is a software development approach in which a system is built incrementally through repeated cycles called iterations. Rather than completing the entire system at once, developers build a small portion, test it, gather feedback, and then refine and expand it in the next cycle.
Each iteration produces a working, functional version of the software — not just documents or plans.
| Feature | Waterfall Model | Iterative Model |
|---|---|---|
| Structure | Linear, sequential | Cyclic, repeated |
| Flexibility | Rigid — hard to go back | Flexible — revisit any phase |
| User Feedback | Only at the end | After every iteration |
| Risk | High (problems found late) | Low (problems found early) |
| Deliverable | One final product | Working increment each cycle |
The Waterfall Model requires each phase to be fully completed before the next begins. If a mistake is found late, it is very costly to fix. Iterative development solves this by allowing continuous improvement.
Each iteration passes through four main stages:
┌─────────────────────────────────────────────┐
│ Iteration N │
│ Planning → Design → Coding → Evaluation │
│ │ │
│ ▼ │
│ Iteration N+1 │
└─────────────────────────────────────────────┘
User-Centered Design (UCD) is a design philosophy that places end-users at the core of the development process. Iterative development is highly compatible with UCD because:
| Iteration | What is Built | What is Tested |
|---|---|---|
| 1 | Student registration module | Basic data entry and storage |
| 2 | Attendance tracking | Accuracy and ease of use |
| 3 | Grade reporting | Report generation and formatting |
| 4 | Parent portal | Login, security, and notifications |
Each iteration delivers a usable piece of the system. By iteration 4, a complete, tested product exists.
| Term | Definition |
|---|---|
| Iteration | A single development cycle (plan → design → code → test) |
| Increment | The working software produced by one iteration |
| Backlog | A list of features/requirements to be addressed in future iterations |
| Feedback Loop | The process of using evaluation results to improve the next iteration |