What you need to know about iterative development

As technology advances rapidly and consumer expectations evolve with it, development teams need a way to design and create new products swiftly without sacrificing quality. This is especially true in digital product and software development.

To improve the software development life cycle (SDLC) to meet the demands of modern technology, many development teams are turning to iterative development.

Iterative development is a product development method that emphasizes flexibility and collaboration by designing, prototyping, and testing smaller features within the overall product. This approach allows development teams to work through the process quickly and limit costs due to errors and unexpected results.

Since the process allows developers to quickly create and test low-cost prototypes, user feedback can be incorporated throughout development to refine the product and deliver optimal results.

There are two ways to guide iterative development:

• Requirement focus: Software products must be functional and user-friendly to meet the needs of target customers. Cycles of iterative development address one or more sets of functional or non-functional requirements to develop the product.

• Solution focus: A software solution typically has several architectural layers. This approach addresses individual layers of the solution during each cycle of development.

Placing the focus on the requirements or elements of the solution enables development teams to establish and refine crucial features early in the development life cycle.

What is iterative development in the SDLC?

While iterative development can be used in all types of product development, it's common in software development. The SDLC is the process used to produce high-quality, low-cost software in the shortest possible production time. It always includes a detailed plan with defined stages that have specific deliverables. Each stage follows the general flow of:

1. Planning

2. Designing

3. Building

4. Releasing

When iterative development is used in the SDLC, developers quickly create a working piece of software by creating early iterations focused on a few requirements. Each release is focused on specific requirements rather than a linear progression that focuses on issues with the previous iteration.

The earliest iterations in the process usually contain the most basic features. Later iterations contain more advanced features and more accurately represent the final product.

Examples of iterative development

Iterative development enables software developers to react quickly to changes as a product evolves. These examples show how this approach improves flexibility during software development.

• Creation of an ecommerce platform: Initial increments of the process focus on basic functionality and essential elements such as a product catalog and checkout. As development advances, product specifications are added and feedback from user testing is incorporated to improve the interface in increments.

• Designing a mobile application: A mobile application designed to achieve a specific task may take a solution-based approach. Developers are likely to focus on a simple interface and tasks that lay the foundation for a multi-layered solution. For example, a user will be able to log in, then create their profile, then send messages.

How long is an iteration in iterative development?

Iterations are a standard, fixed-duration timebox in which development teams deliver one iteration of a product. There is no exact length required for an iteration, but to follow the goals of rapid development, it's generally measured in weeks.

For instance, the Scrum method suggests three to four weeks as the ideal iteration length, but extreme programming (XP) and feature-driven development (FDD) suggest one to two weeks as an ideal duration.

While traditional development and iterative development divide the process into manageable sections, they have contrasting approaches.

Traditional development focuses on developing a product that yields a single completed design before soliciting user feedback. It requires planning, organizing, and controlling project activities to achieve specific objectives that will be reflected in the prototype. Since each phase is considered complete before the next begins, errors are more likely to require substantial reworking.

Conversely, iterative development is the process of creating multiple versions of a product. Developers create a working design that is expected to change throughout the development process. As a result, errors from one iteration don't necessarily affect the production of the next. This enables developers to create iterations in parallel with one another and gain the advantage of getting user feedback early in the process.

In contrast to the iterative approach which enables developers to rapidly create many versions of a product, waterfall development follows a linear process from idea to production. It is a traditional approach to software development in which each stage is dependent on the success of the stage before it.

Planning and requirements for the entire project are done upfront. Development for the full scope is done as one large effort. The team then conducts any testing and releases the full project.

Iterative and incremental development are similar approaches. They are often confused and the terms are frequently used interchangeably. While the methods are similar, there are distinct differences.

Incremental and iterative development are agile methods that enable developers to divide projects into sections. However, the objective of each approach is different.

Iterative development delivers unfinished versions of a product as a whole. Each cycle produces a new version of the software until the best possible product is built.

Incremental development is used to build software in distinct stages. The team delivers one complete element (such as a set of features or design assets) at a time that compiles into a final project.

In other words, iterative development delivers incomplete versions of a whole product, while incremental development delivers finished versions of portions that will work together to create a product. For example, an iteration may produce a low-fidelity prototype with all the features that will be in the final product, but none are actively working yet. An increment may produce a fully functional application with only one feature.

When to use incremental development

Since the cycles in incremental development build off each other, it works best in environments where development teams have a clear idea of the final product. This enables developers to outline a clear objective for each cycle while keeping the overarching goal in mind.

In any design, the product’s initial idea is never identical to its final version. Changes, technical challenges, and new requirements emerge along the way that impact the final product.

How you approach the design process can affect the cost and time consumption these changes require. Iterative development enables engineers to use feedback early and often throughout the process, which has several distinct advantages.

Minimize risks

By producing multiple versions of a product and conducting trials, risks can be identified early in the design process. Early iterations enable developers to create working models to identify design or functionality defects. Recognizing these issues early helps prevent a domino effect in which multiple errors occur due to a single defect.

Gain efficiency

Iterative development has a focused goal of creating a working prototype of a design as quickly as possible. Early iterations are created rapidly to allow engineers to identify and fix problems. Since the process doesn't require the precision of traditional development methods or extensive rework, substantial time is saved.

Improve flexibility

The iterative process is broken down into cycles, allowing for greater adaptability when things don't go as planned. When changes and user feedback are incorporated into the next iteration, developers can eliminate flaws and easily identify ways to improve the product.

Decrease developmental costs

With the use of rapid prototyping technology, developers can easily produce early prototypes at minimal cost. This approach is generally more effective than putting all your resources into a single prototype that might not meet your users' needs. By eliminating the need for full redesigns, you can avoid wasting substantial time and money when flaws are recognized.

Improve quality

Since each iteration is tested and used to gather feedback, you can learn which design details work best. This will enable developers to create the most user-friendly product that meets the desired objectives.

Address user pain points

Users are typically involved in iterative development. User feedback gathered during the design process can be employed to develop more innovative products that accurately address the pain points of your target audience.

While iterative development offers many benefits, it also comes with challenges that are less likely to arise in other methods. Since early iterations of the product don't include all working parts, developers may face the following issues during the process:

• The process can be difficult to manage since iterations can change dramatically from one cycle to the next.

• It may add extra costs and work over smaller, well-structured projects.

• Since developers create many versions of one product, the process can be resource-intensive, especially if iterations have a high failure rate.

• Architectural problems can arise because all the requirements aren't included in early iterations.

While iterative development prioritizes flexibility and versatility, the process needs structure to keep costs low and keep things on track. These are the typical steps involved in any iterative development project.

1. Requirements gathering

The design team meets with stakeholders and other decision-makers to learn the most crucial requirements for the software. Gathering requirements helps the team determine whether the project fits the budget and which elements will be included in the first iteration.

2. Product design

The team uses the product requirements along with experience to design the framework and architecture for the software system. This step will help establish a timeline for the project and the required resources to create multiple versions. Diagrams are used during this phase to plan activities and features and get a clear vision of the scope and complexity of the project.

3. Implementation

Once criteria are evaluated and planning is complete, developers translate the design into code. Engineers integrate the code into a working system that will be the first iteration of the product. The time required for this phase will depend on the complexity of the design and overall scope.

4. Testing

The design team will create a set of guidelines to guide testing requirements. Various tests (such as performance, stress, security, requirements, etc.) are then conducted to evaluate the results and identify errors. Stakeholders and end users may be included in this phase to gather additional insight.

5. Feedback

Test participants provide feedback about the software's performance and areas that should be improved. This step provides valuable insight into flaws or bugs that must be fixed immediately so they don't impact the final development of the product. The development team reviews all feedback to begin planning future iterations.

6. Iteration planning

Based on the feedback from testers, the development team reorganizes the scope of the project, prioritizing crucial features and those that need to be changed from the first iteration. This step is the planning phase for the next steps and future iterations. It provides a clear direction for the complete project.

7. Release and deployment

After multiple iterations, the development team produces software that meets the required objectives. The final iteration is manufactured for production and prepared for release to users. Documentation is drawn up and plans for deployment and post-deployment activities are finalized before the product is released.

8. Review and refinement

In the world of software, product release is not the final step in the development journey. The development team continues to gather feedback from users and monitor software performance. This feedback will be used to further refine the product and introduce new iterations in the form of updates or new versions of the software.