Incremental Model: What It Is and How to Implement It

Mar 30, 2023

When creating a software product, there are a number of software development models to consider—waterfall, Agile, incremental, RAD, iterative, spiral, etc. However, there are several factors to consider when choosing a preferred model. Organizational structure, project goals, testing methods, and the objectives that need to be achieved are among these factors.

Throughout this post, we will examine the incremental development model, which is a common method of software development. We will begin by discussing its characteristics, benefits, and how it works, then compare this model with the waterfall model and discuss its advantages and disadvantages. Finally, we will examine examples of the incremental model and learn how to implement it.

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Incremental Model: What Is It?

It is based on the idea of adding new features, or "increments," to an existing system instead of rebuilding it from scratch each time.

In the incremental approach, software requirements undergo division into stand-alone modules or increments within the SDLC. Phases of development follow once the modules are established, encompassing analysis, design, implementation, testing and maintenance. Each stage builds upon the previously created functionality until the software is completed.

As part of the incremental development model, the development team strives to complete each incremental build in a timely manner. Regular releases represent incremental improvements in functionality and quality, so the goal is to deliver a working product bit by bit.

Incremental models: types

In the software development life cycle, there are two types of incremental models:

Staged delivery model

This kind of incremental delivery model allows for a product or service to be developed and delivered in stages, with each stage building on the previous.

Parallel delivery model

If resources are available, this incremental model can reduce the time required for the development process by building different subsystems concurrently.

Incremental models: characteristics

  • Software projects are divided into smaller, incremental pieces that are developed and tested individually.

  • Until the final increment is completed, the final product is not fully developed.

We prioritize each requirement/stage, and we address the one with the highest priority first.

  • The requirement for a portion is frozen once the incremented portion is developed.

  • To make each incremental version, the iterative waterfall model or other methods are often used.

Incremental Model Phases

It consists of four main phases that help identify and correct defects early in the development process:

Requirements and analysis— Analyzing the project's requirements, including its scope, objectives, and constraints, is the objective of this phase. As part of this phase, the project plan is also defined and the resources required to complete it are identified. Once this document has been created, it undergoes a series of reviews and revisions before moving on to the next step.

Design— During this phase, the project team develops a detailed plan for implementing the project, including the design of the system, the selection of appropriate technologies, and the development of prototypes or proofs of concept.

Coding and implementation— As part of this phase, the project's code is written in accordance with product requirements to implement it. To improve and update product quality, the coding standards need to be adhered to appropriately without using unnecessary hard codes or defaults. This stage also allows for physical execution of the designs.

Test— As a result of this phase, all system components, as well as additional functionality, are tested, integrated, and checked as a whole. Whenever a code implementation is completed, the product should be tested to ensure that it works properly with other pieces of code already written for the project. Once the system is ready for use, it is deployed to production.

SDLC Incremental Models

It divides the software into different modules that can be developed and delivered incrementally. As the plan only considers the next increment, there are no long-term plans during this period. In this way, a version can be altered to meet the needs of the users.

In the development life cycle, the system's fundamental components are created first, followed by additional functionality in subsequent versions. After these features are successfully implemented, they are then improved by adding new functionality in later editions to expand the product's functionality. Each version builds upon the previous one, in an iterative process that follows a waterfall model.

As the software is developed, each new version is delivered to the customer site for testing and feedback, which is taken into account to improve the version.  Once the collection and specification of requirements are complete, the development process is then divided into different versions. Each new version is developed starting with version 1, and then deployed to the client site after each successful increment.

Model Comparison: Incremental vs. Waterfall

In order to improve tracking and development, waterfall and incremental development models are often used. Waterfall development is a linear, sequential process in which each phase must be completed before the next phase can start. It differs in several ways, however. As the development process flows downward in a linear fashion like a waterfall, it's called a "waterfall" model.

An incremental approach involves developing a product and dividing it into smaller chunks (increments) in a sequential manner, whereas a waterfall model entails communication, planning, model construction, production, and deployment. Each increment adds new functionality to the product as it progresses, and it is planned, developed, and tested one at a time.


These models differ in the following ways:

The Incremental Model, also known as the Waterfall Model, offers low costs and is suitable for both small and large teams. It allows for changes to be made easily, although early-stage planning is still necessary. However, it does pose a high-level risk with limited chances for reuse. In this model, the client holds more influence over the administrator who oversees the project. Testing is conducted after each phase iteration, rather than waiting until the development phase is finished. While it's possible to backtrack in earlier steps or phases of the process, this is not feasible in a linear framework like the Waterfall Model. Operating software using this approach may have a relatively short wait time compared to other models that utilize a more lengthy wait time.

Modeling incrementally

Using the incremental model in the SDLC can lower risks and improve project quality. However, it can also provide additional benefits:

Reduced project risk— It is easier for teams to understand and manage risks when projects are broken down into smaller chunks. Identifying risks earlier in the process allows them to reduce or mitigate them because they are testing each aspect of their project in stages.

Improved project quality— Testing in stages allows teams to identify and correct issues before they have a larger impact, so they are more likely to produce high-quality products.

Improved project visibility— By providing regular milestones to work with, the incremental model can help teams improve their project visibility by testing progress, identifying issues, and adjusting their plans as necessary.

Improved team collaboration— By breaking down projects into smaller chunks, teams can better manage their resources and dependencies, improving team collaboration.

Incremental Model Pros

This approach offers several advantages, including the ability to manage risk and increase efficiency. Here are some other benefits:

Improved efficiency— In addition to helping teams plan and organize work more effectively, the incremental model can also reduce the risk of bottlenecks and dependency issues.

Risk-managed progress— Teams can manage risk by testing their project in stages, allowing them to identify and address problems as they arise and make adjustments as necessary.

Clear reporting and tracking— The incremental model allows teams to clearly report and track their progress, thereby improving project visibility and collaboration.

Feedback is possible—In the incremental model, the customer or user can provide feedback at each level to prevent sudden changes.

Meeting goals— In incremental development, all software goals and objectives can be met once the requirements are mapped out.

Incremental Model Cons

Some inherent risks are associated with the incremental model, including:

  • In order to succeed in incrementing, this model must be carefully planned and designed at the beginning.

  • It is possible that teams will lose focus and their project will become uncoordinated.

  • Iteration stages are rigorous, and they do not overlap.

  • Teams that don't plan their work and organize their projects may end up delivering low-quality work and falling behind schedule.

  • Team members may have to continually renegotiate and reprioritize work, resulting in wasted time and effort.

  • In the event of a problem in one unit, it must be fixed in all units, which takes time.

Incremental Models: When to Use Them

When can the incremental model be used?

  • Despite some details evolving over time, the overall objectives of the system remain clear.

  • It's imperative to get a product to market as soon as possible.

  • Consumers expect the product to be readily available as soon as possible.

  • Early market entry is essential for a product's success.

  • The deployment of new technology is underway.

  • There is an inexperienced or unskilled software team.

  • The development timeline of a project is extended.

  • Some features and goals are high-risk.

  • The necessary skills are not available.

An example of a successful incremental model

As users evolve and their demands for better products change, leading software companies use the incremental model. To do this, they evaluate their needs and repeat the SDLC process.

For example, the Linux operating system's kernel, the system's core, was developed incrementally, with each new version building on the previous one, using an incremental approach. This allowed the developers to quickly add new features and functionality to the kernel, and to respond to bugs and other issues promptly. Due to this, Linux has become one of the most widely used and well-respected operating systems on the planet.

Microsoft uses incremental models to make changes to its products on a regular basis to respond to consumer needs. These products come in a variety of versions that are updated as user needs change.

Incremental Modeling Best Practices

To get the most out of the incremental model, teams should first break down their project into smaller chunks, creating a work breakdown structure (WBS). They should then prioritize their work and decide which activities they will perform at which stages. Additionally, teams should develop a project plan and identify the tasks they will perform at each stage, establishing realistic expectations and deadlines for each task.

Moreover, it is crucial for the team to establish a schedule for project reviews and progress updates. These evaluations offer a valuable chance to fine-tune the project and make any necessary modifications. Additionally, utilizing project management tools like Plutora VSM can greatly aid in tracking progress and effectively managing the project. Effective communication and setting realistic expectations for each other are vital in mitigating potential risks associated with the incremental model.

In conclusion

Our post has shown us that the incremental model achieves the desired goal 100% of the time, despite the fact there are many models that can create software. We learned that it's used in the software development life cycle by breaking projects into smaller chunks, which are then developed and tested in stages. As well as reducing project risk, improving project quality, and increasing project efficiency, this development model also offers many advantages.

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