App development has two primary software development life cycle (SDLC) models and methodologies. These are heavyweight or predictive methodologies and lightweight or adaptive methodologies.

A heavyweight development approach involves a predefined scope of work in advance, which is why some developers call it predictive. It requires heavy documentation and significant contribution from programmers and software engineering specialists.

Companies typically choose a heavyweight development approach to organize and streamline extensive projects. Examples of predictive or heavyweight SDLC models and methodologies include:

• The Spiral Model
• The Iterative Model
• The V-Shaped Model
• The Waterfall Model

However, with the recent rise and rapid evolution of the digital market came the heavyweight SDLC model's fall in popularity. That is due to the rigidness toward changes and the linear approach of these methodologies.

These days, more companies are switching to lightweight or adaptive development processes. That is because these methodologies require significantly smaller amounts of documentation with regard to the software life cycle.

A lightweight development approach addresses different client requirements, like the constant application modification necessities. This model contrasts with predictive SDLC models that only grow in complexity when unplanned changes appear.

Adaptive development methodologies are commonly known as rapid application development methodologies or agile models. Examples of adaptive or lightweight SDLC models and methodologies include:

• The Kanban Model
• The Scrum Model
• The XP Model

Most software development clients have trouble differentiating agile from rapid application development these days. This article will discuss RAD, its phases, and its advantages for the client and the final product.

Key Takeaways

• Rapid application development, or RAD for short, focuses on user involvement and constant interaction between designers and users.
• Rapid application development is considerably faster than traditional SDLC but takes similar steps to SDLC in later phases.
• A common drawback of rapid application development is a narrow focus that could lead to limited future development.

What is rapid application development?

Rapid application development or RAD refers to the software development methodology focusing on delivering software as fast as possible. Projects suitable for rapid application development typically have well-defined and narrow business objectives and a focused scope.

The nature of rapid application development entails a requirement of only a small number of people involved in project decisions. Because of the emphasis on quick development time, there is little to no room for project management bureaucracy. That is why a small team of six or fewer people is ideal for rapid application development.

Rapid application development focuses less on planning and more on working prototypes and quick feedback from clients and end-users. The RAD process affords developers the speed and flexibility traditional waterfall methodologies cannot. It enables the development of applications in the shortest time frame and allows changes midstream depending on user requirements.

In other iterations, it is a faster adaptation of the linear sequential model using component-based construction. That means it follows the linear sequential model but uses separate teams to work on specific components. Eventually, each component will integrate to make up the final working product or software.

The core elements of rapid application development include:

• Data modeling
• Business modeling
• Process modeling
• RAD tools
• Application generation
• Testing and turnover

The rapid application development methodology consists of four phases:

• The requirement planning phase
• The user design phase
• The construction phase
• The cutover phase

Here are their definitions.

The requirement planning phase

This phase in the RAD model is the equivalent of a project scoping meeting. However, the RAD methodology planning phase is more condensed than other project management methodologies. The requirements planning phase is arguably the most crucial step that dictates the success or failure of a RAD project.

During this phase, software end-users, team members, and developers communicate to define expectations and goals for their projects. They also discuss all the potential and current problems that need addressing during the construction phase of the software.

There are many different ways software developers conduct this phase, but they always follow three primary stages within it. These three stages of the requirement planning phase are:

• The research on current and potential problems
• The definition of project requirements like functionality and features
• The finalization of requirements with approval from each stakeholder

During the first phase, rapid application development does not require a detailed list of specifications from end users. Instead, it only requires a broad definition of requirements. That affords developers the time to segment specific application requirements at different points of the software development life cycle.

A crucial part of this phase is that all parties involved have the opportunity to evaluate project expectations and goals. That way, developers, team members, and clients can weigh in on every part of its development. When you have approval from all developers and key stakeholders, it avoids any miscommunication and expensive order changes long term.

The user design phase

This phase of the RAD model involves jumping straight into development immediately after defining the project scope. That means generating the user design through different prototype iterations.

The user design phase is the bulk of rapid application development methodology, which separates it from other project management methods.

During the user design phase, developers work with the clients who provide user feedback regarding the prototypes. That ensures they meet the requirements and specifications at every step of the design process. It is similar to customizable software development in that the users can test each prototype during every stage of development.

A loose and popular example of this is an early-access game for sale on Steam or other gaming library platforms. Early-access games are typically more robust demo versions of a game developed by small or independent developers.

These developers either want to get ahead of the market or need more funds to complete the project. Early-access games afford these developers much-needed marketing, funds, and user feedback to finish developing and refining their games. The basic premise is having users pay for an incomplete game version with the promise of completing it later.

During the user design phase, they can work out all the kinks and bugs in an iterative process. The basic principles are that the developer creates a prototype, and the user or client tests it. After that, they constantly communicate what works and what does not.

It enables developers to make tweaks they go until they reach a design their client finds satisfactory. It is like real-time quality control because developers and clients can ensure no potential problems are left to slip through the cracks.

The construction phase

The construction phase takes the beta systems and prototypes from the user design phase to convert them into a working model. Most issues and changes have been addressed during the iterative user design phase. That enables developers to build a final working model significantly faster than they could with a traditional project management approach.

There are many different styles to execute this phase, and some companies even add extra steps. However, the phase breaks down into four main smaller steps that include:

• Rapid construction preparation
• Coding
• Application and program development
• Unit, system testing, and integration

During this phase, the software development team's coders, testers, developers, and programmers combine their efforts. That is to ensure the application works smoothly and its result fulfills the client’s objectives and expectations.

The importance of the construction phase lies in the client's ability to provide input during the process. Clients can provide suggestions for changes, alterations, or even new concepts that can solve issues as they appear.

The cutover phase

The cutover phase is also known as the implementation phase. This phase is where the finished product gets launched. It also includes testing, user training, data conversion, and changeover into the latest system. It is the final change while the clients and coders continue to check for bugs in the final product.

Did you know?

The first rapid application development alternative was the spiral model, a risk-driven development process developed by Barry Boehm.

What are the advantages of the rapid application development model?

One way to appreciate the value of the rapid application development methodology is by comparing it to the waterfall methodology. Several years ago, the waterfall methodology was somewhat standard for managing projects.

Like other SDLC methodologies, the waterfall model has phases implemented in a linear sequential way. In it, progress flows downward in a single direction like a waterfall, hence the name waterfall methodology. Each phase defines a specific stage, and each completes before the next one can begin execution.

This approach demands that projects finish within a fixed budget, have a rigid scope, set schedule, and have excellent quality. However, most software development teams often fail to meet all these requirements, resulting in an unsatisfied client. Even when projects meet the specified budget, time, scope, and quality standards, it could still result in an unsatisfied client.

The traditional waterfall approach does not require much customer communication and involvement until the final product is completed. That means there is no room for user feedback or suggestions for changes until after the deployment phase.

As a result, clients may have different needs by the time of release that the current final product does not meet. This problem can significantly affect customer satisfaction and the overall quality of the final product.

That is why most businesses shifted to using rapid application development approaches over the traditional waterfall. Here are some benefits rapid application development can provide.

Faster delivery

As the name implies, rapid application development provides quicker end delivery of applications. That is because it takes less planning time and affords client input to help finish a project faster.

High adaptability

Suggestions for changes and alterations often take place during the development process. Rapid application development provides a framework where the development team can make adjustments midstream. If a client wants something added, removed, or adjusted, RAD makes it easy for both the client and the development team.

Proactive damage control

No matter how well anyone develops an application, there will always be issues like bugs and design oversights. A typical problem for traditional waterfall methodologies is that these issues come out after release. That makes finding, mitigating, and fixing these issues significantly more complex than doing all of that during the development phases.

The rapid application approach helps developers and clients detect current and potential problems before the software's completion. That way, it minimizes any glaring errors in the system that may appear after its launch.

Additionally, it provides clients with significant insight into how their software is made and how they function. That means that should a problem arise; clients know where to find the root of the issue.

Lower development expenses

There are cases where rapid application development requires more funding for talented developers when compared with other methodologies. However, since RAD shortens the development time, the costs may turn out to be the same, if not cheaper.

Rapid application development is particularly cost-efficient when a client needs to make massive changes. That is because it does not require a complete restart in the development process for significant changes. As a result, considerable adjustments do not cause more cost overruns.

Better adoption of new technologies and integrations

In the current digital landscape, there are always new technologies and integrations where you can incorporate your application. Unfortunately, the waterfall methodology involves too much work, cost, and risk to restart and change software requirements. Additionally, integrating with other software is the last thing that comes to mind with this methodology.

With RAD, development teams can immediately test and evaluate their software’s new integrations and technologies. They can check for things that work with their software and what do not and determine how each affects performance. Even in cases where they do not work with your software, RAD provides developers space to create compatibility solutions.

Speed Up the Development Process With Rapid Application Development

While the rapid application methodology certainly has its strengths, it is far from perfect. RAD involves high-cost code generation and well-defined requirements before starting a project and lacks structure found in other methods. However, as mentioned, the speed and adaptability that results in improved customer satisfaction and software quality are its ultimate selling points.

If you are still unsure if RAD is for you, consider consulting trusted software development experts before deciding. After all, choosing the suitable methodology for developing an application can affect its success or failure.

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