Incremental Development Model

Incremental Development Model

It is also called the successive version model or evolutionary model. Incremental development is based on the idea of developing the initial implementation, getting feedback from users and evolving software through several versions until the required software has been deployed and developed.


  • At first, a simple working model is built.

  • Subsequently, it undergoes functional improvement and we keep on adding new functions till the desired system is built.

  • This approach interleaves the activity of specification from our development and validation.

  • The system is developed as a series of versions which is also known as increments with each version adding functionality to the previous version.

Incremental model

The typical phases in incremental development in software engineering are usually as follows:

  1. Specification (Initial Version):

    • This phase involves gathering and defining the requirements for the software. The goal is to create a clear and comprehensive specification that outlines what the software is supposed to achieve.
  2. Development (Intermediate Versions):

    • In this phase, the software is developed in increments or smaller iterations. Instead of creating the entire system at once, developers work on smaller, manageable portions. Each increment typically adds new functionality or refines existing features.
  3. Validation (Final Version):

    • After each increment is developed, it undergoes validation to ensure that it meets the specified requirements and functions as intended. This phase involves testing and quality assurance to identify and fix any issues.
  4. Repeat (Cycle):

    • The development, validation, and specification phases are repeated for each increment until the complete system is built. Each cycle adds new features or refines existing ones based on feedback from previous increments.

It's important to note that the order of the phases is typically Specification, Development, Validation, and then the cycle repeats. The "Final Version" is the culmination of several iterations or increments, and it represents the complete and validated software.


  1. The cost of implementation requirements changes is reduced. The amount of analysis and documentation that has to be redone is significantly less than is required with the waterfall model.

  2. It is easier to get customer feedback on the development world that has been done Customer can comment on the demonstration of the software and see how much has been implemented

  3. Every delivery and development of useful software to the customer is possible, even if all of the functionality has been included Customers can use and gain value from the software earlier than is possible with the waterfall model.

  4. Users get a chance to experiment partially developed system.

  5. Reduce the error, because the core modules get tested thoroughly.

Disadvantage:- It is difficult to divide the problem into several versions that would be acceptable to the customer, which can be incrementally implemented and delivered.


  • Large projects where you can easily find modules for incremental implementation.

  • Often used when the customer wants to start using the core features rather than waiting for the full software.

  • Used in object-oriented software development because the system can be easily portioned into units in terms of objects.

The incremental development approach allows for flexibility and adaptability throughout the software development process. It enables developers to respond to changing requirements and incorporate feedback from users or stakeholders at various stages of the project. This approach is in contrast to traditional waterfall models where the entire system is developed linearly, and changes are difficult to implement once the process is underway.