Iterative vs Incremental Development: An All-Inclusive Comparison

Priyanka Ghosh

By : Priyanka Ghosh

Iterative vs Incremental Development: An All-Inclusive Comparison1

Summary: Iterative vs Incremental

The fate of your project depends largely on the type of development chosen. It can affect the development cycle, product quality, development speed, and so on. In today’s competitive market, if your development method isn’t full-proof, you may lose time and money.

In this respect, you might have heard of the most sought-after methodology ‘Agile.’ Did you know that projects using Agile development see about a 64% success rate, as per reports? They are about 1.5x more successful than Waterfall projects.
If you have heard of Agile, you might have heard of Iterative vs. Incremental: the two development methodologies combinedly used for Agile. And if you are confused about how they work and how they are different from one another, this blog is for you.
It will also make it easier to work with a web development company as you will be better informed about the development methodology used.

What is Iterative Development?

In iterative development, you can break the entire development cycle of a large product into smaller chunks. Here, each iteration represents a repeat cycle where the design, development, and testing of elements are performed.

Here, the development starts with the basic idea that you have in mind. It is a feedback-based model, where each iteration is a better version of the previous one based on feedback. And as you move from one iteration to another, you build upon it.

Example of Iterative Development

Example of Iterative Development
Let’s take an eCommerce project to understand iterative development.

If you are developing an eCommerce website, the first iteration will include all primary functions, such as user profiles, a checkout page, a shopping cart, favorites, and customer reviews. After these functionalities are designed, developed, and tested, feedback is collected.

Based on the feedback, you improvise the various eCommerce features. Again, the software is developed and tested, and feedback is collected. This is how iterative development works until you get a refined product.

Iterative Development Process

Iterative Development Process
In Iterative process development, these five steps are repeated in each iteration until you get the desired result.

  • Planning & requirement: In the first stage, you plan the initial requirements of the software, collect related documents, and devise a timeline or strategy for the first iteration, You can consider using software documentation tools to keep for documentation.
  • Analysis & design: It starts with analyzing your business needs, tech requirements, and database models. Then, you design a mockup, prototype, algorithm, or working architecture for your project.
  • Implementation: Design and develop based on the strategies formed.
  • Testing: The testing phase helps you locate things that aren’t working per expectations. Testers, stakeholders, clients, and users provide valuable feedback for the next iteration.
  • Evaluation & review: You need to compare the iterative delivery of this iteration with your project requirements and expectations. If everything is not per it, you must repeat these steps in the next iteration.

What is Incremental Development?

The Incremental development model visualizes the end product from the get to. Then, the project is divided into multiple parts that are developed separately, piece by piece. Meaning at the end of each phase, you will get a functional product that does not need to be reviewed any further.

The next subsection will include more user-visible functionalities. The delivery of the final product is only possible after all the sections are finished developing.

Example of Increment Development

Example of Increment Development
Let’s take an eCommerce project to understand incremental development.

When developing an eCommerce store using this process, you envision the final product with all the necessary features. It can be search filters, product pages, a shopping cart, customer reviews, customer support, etc.

Then, you divide the entire project into multiple parts; where the first part contains basic functionalities, and you add more advanced features with each section. For instance, you can build the product page, cart, and checkout pages in the first phase.

Whereas the second phase will include tasks like adding products to the wishlist, sharing with friends, checking customer reviews, etc.

Incremental Development Process

Incremental Development Process

Like iterative development, the project is divided into multiple chunks and developed separately here. However, the various builds aren’t developed simultaneously but in order. The first build will include all basic functionalities, and the second will have added features and functionalities.

After the requirement is analyzed, the product is divided into multiple builds. In the incremental development model, each build consists of the following three steps:

  • Design & Development: In this phase, you need to design and develop based on the scope of the build.
  • Testing: The designed and developed code is tested for accuracy. You can locate any errors and issues in this step and send them back to the development team for optimization.
  • Implementation: Once the testing phase is complete, the developed and designed elements are checked, and the final product is upgraded after every build.

Advantages & Disadvantages of Iterative Development

Advantages

  • Smaller iterations in Iterative software development make testing and debugging easier.
  • You can easily identify any risks during the iterations and resolve them from progressing.
  • Apt for projects with ever-changing requirements.
  • Parallel development is possible.
  • You don’t have to spend more time on documentation and instead can focus on the designing part.

Disadvantages

  • It might not be suitable for smaller iterative software development projects.
  • You need more resources to work in multiple iterations.
  • The design may change numerous times because of no definite requirement or based on feedback.
  • Budget exhaustion because of change in requirement.
  • You can’t give a project completion date or timeline as the project scope might change over time.

When to Use Iterative Project Management?

  • For large software applications
  • Easy-to-understand and clearly defined requirements
  • If the project has to be flexible and requirements can change over time

Advantages & Disadvantages of Incremental Development

Advantages

  • Very flexible
  • Easy to recognize errors
  • Easy testing and debugging
  • Important features can be developed in early builds
  • Simple risk management as it is handled in the individual builds

Disadvantages

  • High costs
  • Proper planning is required
  • Appropriately defined modules are needed

When to Use Incremental Process?

  • Projects with lengthy development schedules
  • When a client needs a quick product release
  • In case priority features are needed first
  • When there’s a limited number of resources

These pros and cons of Iterative and Incremental development should help you understand the places where they can be used. Now, you don’t always need to compare incremental vs. iterative and find the best amongst the two.

Few projects might use both! You might have heard of agile methodology using incremental and iterative development. In Iterative and Incremental development in Agile, the project is divided into multiple sprints (much like the Iterative approach). Just that the iterative approach uses iterations, and the agile approach uses sprints. Another Agile iteration vs. sprint difference to note!

However, it is assumed to be successful only if a valued work product is obtained. That’s one of the key differences between Agile vs. Iterative.

Read Also: A Layman’s Guide to Agile & Scrum

Incremental Development

Difference Between Iterative vs Incremental Development

To further help you understand the key differences between the two development methods, I have created the table below.

Iterative Incremental
Approach Here, the product is developed in multiple iterations. So, the product wireframe is created in the multiple first iterations and then revised for quality/ feature improvements. Here, the entire product is built piece by piece. So, until and unless you reach the last build, the product won’t be ready.
Error Identification Each iteration is a complete variation of its own. Thus, error identification and rectification become simpler. Even though each sub-part is developed independently and tested, there may still be errors after the final assembly. It makes it impossible to identify errors from the beginning.
Product Quality Numerous cycles are needed to get a quality product. The number of cycles is comparatively less.
Completion Time You can finish development in a little time. The incremental delivery in agile takes longer to finish a project.
Costs If the number of iterations is huge, the project’s cost will increase. The development and testing are done in one iteration mostly and are cost-effective.
User Engagement More engagement with users as feedback is collected after each iteration. User engagement is less comparatively as feedback is received periodically.
Risk Mitigation Since every iteration is tested, risks are identified and resolved in time. The complete product takes longer to develop. Thus, more possibility of risks in the later stages.
Adaptability You can easily deal with unexpected changes in project requirements in the next iteration. Since it follows a rigid process, the entire software development lifecycle can be delayed.

 

Conclusion

The development method you choose can define the ease or difficulty you will face during the entire SDLC. Thus, it is best to learn about the ins and outs of Iterative vs. Incremental development I have mentioned here.

It should help you decide the best approach to your software development. And in case you are looking for a technical team that can handle it seamlessly, we’re happy to help. Our team excels in software development using agile methodologies (both incremental and iterative). Connect with us to know more.

FAQs

Is the waterfall model iterative or incremental?

It is none of the two iterative or incremental development models. In the waterfall approach, the entire software is developed in a go.

What is the difference between agile, incremental, and iterative?

The Incremental model, divides the productnto multiple subparts and is developed in increments. Most basic/essential features are developed first, followed by other sections, and the end product is achieved by assembling all the parts.
The iterative model divides the product into multiple iterations. Each iteration has to go through the five steps of planning, designing, development, testing, and evaluation. Another iteration is executed based on the feedback received in the final step.
An agile approach can be both Incremental and Iterative.

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