Difference between V-Model and WaterFall Model

Differences Software & Coding Web Development

Both the Waterfall model and the V-Model are quite widely used development methodologies in the software industry. Both of these models help the development of applications in a systematic way. The basic difference between V-Model and Waterfall model is that, in the V-Model, defects are identified in the testing phase, while in the Waterfall model, defects are identified from the beginning.

Read through this article to find out more about the V-Model and the Waterfall Model and how they are different from each other.

What is V-Model?

V-Model is the development model in which the entire model is divided into various sub development phase where corresponding testing phase for each development phase is practices. It is an important model used in the process of application testing. The V-Model is also known as Verification and Validation Model.

It works in a sequential method in which the next phase being started only after the completion of the next phase. In V-Model, the requirement of specification is necessary in the beginning. There is more customer involvement in the V-Model; it is an expensive model of software development.

What is Waterfall Model?

In the Waterfall model, there is first development of the application and after which the different testing of application take place. Waterfall model is similar to the V-Model in terms of execution of processes.

In the waterfall model, the testing activities being started after the development activities are completed. The errors and defects in the developed applications using the waterfall model are comparatively less than the applications developed using the V-Model.

The waterfall model requires less customer involvement. In this model, the identification of defects is done in the testing phase, while debugging is done after the last phase. The Waterfall model is comparatively less expensive than the V-Model.

Difference between V-Model and Waterfall Model

The following table highlights the major differences between the V-Model and the Waterfall Model on the basis of the type of steps or phases involved in these two software development methodologies −

Parameter	V-Model	WaterFall Model
Definition	V-Model is the development model in which the entire model is divided into various sub-development phases where the corresponding testing phase for each development phase is practiced. For every stage in the development cycle, there is an associated testing phase and the corresponding testing phase of the development phase is planned in parallel.	In the Waterfall model, an application is developed first, after which it is tested using different testing techniques. The complete process is divided into several phases among which one phase should be completed in order to reach the next phase and testing is almost at end phase of the development.
Type/Nature	In the V-Model, the execution of the phases i.e., development and testing happens in a sequential manner so type of V-Model is Sequential/Parallel in nature.	Waterfall Model is a relatively linear sequential design approach as each phase should be completed in order to reach the next phase. So type of this model is Continuous in nature.
Testing and Validation	In the V-Model, each development phase get tested at its own level and hence no pending testing occurs in this model also if any validation requires to be implemented then it could be implemented at that phase.	In the Waterfall Model, the testing occurs after development is completed and thus if any missing validation is identified to be implemented then first that phase of development needs to be recognized and then that validation get implemented.
Cost and Complexity	As sequential phases need to be functional in case of V-Model hence the cost is higher as compared to that of WaterFall Model also the complexity is more than WaterFall.	In the Waterfall Model, due to linear development, only one phase of development is operational and hence cost and complexity is low as compared to that of V-Model.
Defects	In the V-Model, the probability of total number of defects in the development of application is low as testing is done in parallel to the development.	In the Waterfall Model, the probability of total number of defects in the development of application is high as testing is done post development.

Conclusion

The most significant difference that you should note here is that, in the V-Model, the testing activities start with the first stage, while in the Waterfall model, the testing activities start only after the development activities are over.