Project Management guide · Project management fundamentals
Iterative and Incremental Development Explained
Iterative and incremental development are two related ideas behind most modern delivery approaches. Iterative means improving through repeated cycles; incremental means delivering in usable pieces.
Key takeaways
- Iterative means improving through cycles; incremental means delivering in pieces.
- Agile combines both.
- Use them when requirements are uncertain.
Definitions
| Iterative | Incremental | |
|---|---|---|
| Idea | Refine the solution through repeated cycles | Build the solution piece by piece |
| Example | A rough design improved over several reviews | Login first, then search, then payments |
| Benefit | Learning and quality improve each cycle | Users get value sooner |
Using both together
Agile frameworks such as Scrum combine both: each Sprint delivers a usable increment, and each cycle improves earlier work based on feedback. The result is early value plus continuous learning.
History
Iterative and incremental development has been used since at least the 1950s and 1960s on large engineering programmes, long before the word Agile was coined. See the history of Agile.
When to use it
- Requirements are uncertain or likely to change.
- Early feedback from users is valuable.
- The solution can be delivered and used in parts.
- Risk needs to be reduced step by step.
Frequently asked questions
Is iterative development the same as Agile?
Agile uses iterative and incremental development, but adds values such as customer collaboration and self-organising teams.
Can Waterfall projects use iterative development?
Some predictive projects add iterations within phases, especially for design and prototyping.
What is iterative development?
Refining a solution through repeated cycles, improving it each time based on feedback.
What is incremental development?
Building a solution piece by piece, with each increment adding usable functionality.
What is the difference between iterative development and incremental development?
Iterative improves the same thing through repeated cycles; incremental adds new pieces. Agile frameworks combine both.
What is an example of incremental development?
Releasing login first, then search, then payments, so users get value from each piece as it is ready.
What is an example of iterative development?
Producing a rough design and improving it over several reviews with users until it meets their needs.
When should you use iterative and incremental development?
When requirements are uncertain, early feedback is valuable, the solution can be used in parts and risk needs to be reduced step by step.
How old is iterative development?
It has been used since at least the 1950s and 1960s on large engineering programmes. See the history of Agile.
What is the spiral model of iterative development?
A risk-driven iterative model described by Barry Boehm in the 1980s, in which each loop plans, analyses risk, builds and evaluates.
Does Scrum use iterative or incremental development?
Both. Each Sprint delivers a usable Increment, and each cycle improves earlier work based on feedback.