Evolutionary Model in Software Engineering

Evolutionary Model in Software Engineering

The concept of the evolutionary model in software engineering came into picture when the users wanted to experience the partially developed system rather than waiting for the fully developed version. Thus, the evolutionary model is based on the idea of developing the core modules, then gradually improving the software product over time using incremental and iterative techniques with appropriate feedback. 

In this type of process model, successive versions of the product are made through several iterations and come up when the final product is built through multiple iterations. The evolutionary approach suggests breaking down modules into maintainable smaller chunks, prioritizing them and then delivering those chunks one at a time to the users. 

It is important in large projects where you can easily find modules for incremental implementation. Evolutionary model is one of the important models as it involves customer feedback throughout the development process and the customers can start using the core features much before the full working version is released. It is also important in object oriented software development because the system can be easily divided into functional units in terms of objects.

What is the Evolutionary Model?

Evolutionary model(aka successive versions or incremental model) aims to deliver products  in incremental processes over time. It is a combination of Iterative and Incremental model of software development life cycle.

The Evolutionary development model divides the development cycle into several modules that can be built and transferred incrementally. In other words, you develop an initial product skeleton and refine into increasing levels of capability by adding new functionalities in successive versions.

Characteristics of the Evolutionary Model 

  • Each evolutionary model may be developed using an iterative waterfall model of development.

  • Evolutionary models include three types- Iterative model, Incremental model and Spiral model.

  • The models require several primary needs and architectural planning that must be done.

  • The new release of the product may include new functionality and also a modification in the existing functionality.

  • This model allows for changing requirements as well as dividing the development process into different manageable work modules.

  • The development team responds to customer feedback on the product throughout the planning phase of the next cycle, frequently by altering the product, strategy, or process. 

Comparison of Evolutionary Model with other Models 

Evolutionary Model vs Incremental Model

Evolutionary Incremental
The requirements are not clear and they change as the development progresses. The requirements are clear to the development team.
The initial step involves understanding the customer’s requirements,  developing the core modules and functionalities and delivering them to customers for feedback.Each module is refined into multiple iterations by adding new functionality, and in the end, a deliverable product is released.
For each version, the complete cycle of activities is repeated. Each increment is developed, tested, and released at various intervals of time.
The development team is unsure of how much has been completed and how much still has to be done.The development team knows how much has been completed and how much needs to be completed soon.

Evolutionary Model vs Iterative Model

Evolutionary Iterative
Before release of the final product, different modules are released in incremental manner.It follows a sequential development process and the software is released all at once.
The delivery of the actual product can be late.The actual product is delivered within the time frame with all requirements.
Module integration is difficult.It is easy to understand and implement.
It is only suitable for large projects.Iterative model is the most commonly used model for projects.

Evolutionary Model vs Classical Waterfall Model

EvolutionaryClassical Waterfall
This model deals with different versions of the software.It has defined phases mentioned in an order.
Integration can be hard.Simple to use, understand and implement.
Evolutionary models involve customer feedback during development.There is no option for customer feedback.
Errors are detected in the core modules.Errors are detected at the end of every phase.
With every new release new functionalities are added and the existing functionalities may be updated.Once the development has begun, new features cannot be added or updated in the software.

Evolutionary Model vs Spiral Model

Software is developed through different modules in an incremental manner. The modules are divided into loops which are further divided into four quadrants.
Suitable for large projects.Suitable for development of technically difficult software products  that are vulnerable to different threats. 
Every version is capable of fully functioning the mentioned functionalities.Each block of the model contains a set of activities that the software performs.

Advantages of the Evolutionary Model

  1. In the evolutionary model, users get a chance to experiment with the partially developed product much before the fully developed product is released.
  2. Core modules get tested thoroughly which reduces the chances of errors in the final product.
  3. Suitable for large projects.
  4. The model is better for software products that have their feature sets modified throughout the development process because of customer feedback and other factors.
  5. Evolutionary models help finding exact user requirements during the delivery of different versions of the software.
  6. At the end of each cycle, users can access the product. 
  7. The use of an evolutionary model removes the requirement to allocate significant resources all at once for system development.

Disadvantages of the Evolutionary Model

  1. Often, it is difficult to subdivide problems into functional units that would be acceptable to the customer which can be incrementally implemented and delivered.
  2. The delivery of fully developed software can be late and the market can go down due to different changes by customers during development.
  3. Risk is high and there is always a need to report customers continuously.


The evolutionary model is very helpful in finding the user requirements while the delivery of various versions. Each version is developed with customer feedback and the error is detected in the core modules leading to less errors and resolved for better utilization. This model eliminates the need to release a software project all at once rather than dividing it, delivering it, fixing the issue, adding new features, releasing a new complete version, and finally assisting in establishing trust between the client and the development team.

The model is a flexible and adaptable approach that can be beneficial for certain projects, but it also has its limitations. It is important for software developers to carefully consider the characteristics and requirements of their project before choosing a software development model.

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