Incremental Model in SDLC

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.

What is Incremental model in SDLC? Advantages & Disadvantages

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 PhasesActivities performed in incremental phases
Requirement AnalysisRequirement and specification of the software are collected
DesignSome high-end function are designed during this stage
CodeCoding of software is done during this stage
TestOnce 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

AdvantagesDisadvantages
The software will be generated quickly during the software life cycleIt requires a good planning designing
It is flexible and less expensive to change requirements and scopeProblems 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 doneEach iteration phase is rigid and does not overlap each other
This model is less costly compared to othersRectifying a problem in one unit requires correction in all the units and consumes a lot of time