Difference Between Waterfall Model and Incremental Model

The waterfall model and incremental model both are the prescriptive process models but they can be differentiated on many aspects such as flexibility of the delivered software, the risk involved, testing of software, maintenance, customer involvement, etc.

Quick Comparison: Waterfall Model Vs Incremental Model

BasisWaterfall ModelIncremental Model
Working VersionThe working version of the software is delivered at end of the model’s life cycle.The working version of the software is delivered in each iteration.
Work FlowThis model proposes a sequential workflow.This model proposes a linear and parallel workflow.
User InvolvementUser involvement occurs in the first phase of the model i.e. communication.The user involvement occurs in first phase of each iteration.
FeasibilityThis process model does not accommodate changes in the software.This process model accommodates changes in software easily.
Team SizeTeam size is large.Does not require a large team.
DocumentationFocuses too much on documentation.Provides documentation but not enough.
MaintenanceThis model provides the least maintenance.This model promotes maintenance.
TestingAfter the coding phase completes.At each iteration.
RetrackingNot possible.Possible.

Waterfall Model

The waterfall model is a software development model that develops software by dividing the entire process into independent phases that have to be processed one after another in a sequential manner.

The independent phases incorporate communication, planning, modeling, construction, and deployment. Each phase is processed until the final product of the phase arrives which is then provided as an input to the next phase. The figure below shows the workflow of the waterfall model.

Waterfall model and increamental model

Incremental Model

The incremental model is also a software development model that can be used in a situation where the requirements are not well defined initially. The incremental model pursues all the steps required to develop the software in a linear and parallel fashion as you can see in the figure below.

Waterfall model and increamental model2

In the incremental model, the working version of the software is delivered in the first iteration itself, and in the latter iteration, the supplementary and advanced features are added to the software. With this model, the changes can be accommodated to the software easily as it can be retracted.

Difference Between Waterfall Model and Incremental Model

  1. Working Version: The working version of the waterfall model is delivered in the deployment phase i.e. the last phase of the waterfall model whereas the working version of an incremental model incorporating basic requirements is delivered in the first increment and supplementary features are delivered in a later iteration.
  2. Work Flow: In the waterfall model follows sequential workflow which incorporates communication, planning, modeling, construction, deployment phases one after the other respectively. The incremental model follows the linear along with the parallel workflow which means that before delivering the first working version of the software the team starts processing phases for the second incremental working phase and so on.
  3. User Involvement: In the waterfall model the user involves while addressing the requirements in the communication phase. However, in the incremental model, the communication phase occurs in each iteration so the user gets involved in each iteration.
  4. Feasibility: In the waterfall model once, the software is deployed there is no chance to accommodate any change as there is no trackback. In the incremental model, the changes can be accommodated easily as during the later iteration.
  5. Team Size: The waterfall model requires a large team size. However, the incremental model does not require a large team size.
  6. Documentation: In the waterfall model, everything in every phase is documented and hence there is too much documentation whereas, comparatively there is less documentation in the incremental model.
  7. Maintenance: In the waterfall model, there are very least chances of providing maintenance as after deploying the product the user is hardly approached for maintenance. On the other hand, the incremental model promotes maintenance.
  8. Testing: In the waterfall model testing of the software is done once after the coding phase is completed whereas in the incremental model testing is performed at each iteration.
  9. Retracking: In the waterfall model, retracking is impossible as there is no provision to return back to the earlier phase. However, in the incremental model, retracking is possible as at each iteration the earlier phases are processed.

This how both the prescriptive models differ from each other. We have tried to differentiate both the models on all the possible aspects. Hope you can differentiate between both the models now.

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