Incremental Model in SDLC: Use, Advantage & Disadvantage

What is Incremental Model?

Incremental Model is a process of software development where requirements are broken down into multiple standalone modules of software development cycle. Incremental development is done in steps from analysis design, implementation, testing/verification, maintenance.

Each iteration passes through the requirements, design, coding and testing phases. And each subsequent release of the system adds function to the previous release until all designed functionality has been implemented.

The system is put into production when the first increment is delivered. The first increment is often a core product where the basic requirements are addressed, and supplementary features are added in the next increments. Once the core product is analyzed by the client, there is plan development for the next increment.

Characteristics of an Incremental module includes

System development is broken down into many mini development projects
Partial systems are successively built to produce a final total system
Highest priority requirement is tackled first
Once the requirement is developed, requirement for that increment are frozen

Incremental Phases	Activities performed in incremental phases
Requirement Analysis	Requirement and specification of the software are collected
Design	Some high-end function are designed during this stage
Code	Coding of software is done during this stage
Test	Once the system is deployed, it goes through the testing phase

When to use Incremental models?

Requirements of the system are clearly understood
When demand for an early release of a product arises
When software engineering team are not very well skilled or trained
When high-risk features and goals are involved
Such methodology is more in use for web application and product based companies

Advantages and Disadvantages of Incremental Model

Advantages	Disadvantages
The software will be generated quickly during the software life cycle	It requires a good planning designing
It is flexible and less expensive to change requirements and scope	Problems might cause due to system architecture as such not all requirements collected up front for the entire software lifecycle
Throughout the development stages changes can be done	Each iteration phase is rigid and does not overlap each other
This model is less costly compared to others	Rectifying a problem in one unit requires correction in all the units and consumes a lot of time
A customer can respond to each building
Errors are easy to be identified