Project management: Agile vs. Waterfall

Overview

In the realm of project management, two prominent methodologies have emerged as popular choices for executing and delivering projects: Waterfall and Agile. While both approaches have their merits, they differ significantly in terms of planning, execution, flexibility, and adaptability. In this blog, we will delve into the characteristics, benefits, and limitations of the Waterfall and Agile methodologies, providing readers with valuable insights to help them make informed decisions when selecting the most suitable approach for their projects. Let's start analyzing Agile vs. Waterfall!

The Waterfall methodology

Let's explore the fundamental phases of the Waterfall methodology:

Requirements gathering

In the requirements gathering phase, the project team works closely with stakeholders to define and document the project's requirements. This involves understanding the desired functionalities, goals, and constraints of the project. At the end of this phase, the team finalizes a comprehensive requirements document that serves as the foundation for subsequent phases.

Design and analysis

Once the requirements are gathered and documented, the design phase begins. Designers and architects develop a detailed plan to meet the project requirements.

Within the design phase of the waterfall model, there are multiple steps, each handling a different design aspect. This includes creating system architecture, designing user interfaces, and defining the technical specifications among others.

Development

In the development phase, the actual coding and implementation of the project take place. Developers use the aforementioned design specifications to build the software or create the product. This phase involves translating the design into executable code, conducting coding reviews, and adhering to coding standards.

Testing

After the development phase, testing is conducted to verify the product's quality, functionality, and adherence to requirements. Testers perform various types of testing, including unit testing, integration testing, system testing, and user acceptance testing. The goal is to identify and resolve any defects or issues before moving forward.

Deployment

Once the product passes all the testing phases and meets the required quality standards, it is ready for deployment. The deployment phase involves installing the product or releasing it to the end-users. This may include activities such as installation, configuration, data migration, and training for users.

Maintenance

After deployment, the maintenance phase begins, where ongoing support and updates are provided. This phase ensures that the product remains functional and reliable. It involves activities such as bug fixes, updates, enhancements, and addressing customer feedback.

Advantages

• The Waterfall methodology is predictable, and the project requirements are well-defined at the beginning of the project. This helps the team to plan the project in advance, and it is easier to estimate the project timeline and budget.

• The Waterfall methodology has clear roles and responsibilities for each team member, and the project manager has more control over the project.

• The Waterfall methodology requires documentation of the project at each phase. This documentation helps the team to track the project progress, identify issues, and plan the project accordingly.

Disadvantages

• The Waterfall methodology follows a rigid process, and it is difficult to change the project requirements once the project has started. On average, 20 to 25 percent of a project’s requirements change while it’s underway. As all the requirements have already been extensively outlined in a previous phase, a portion of the work becomes repetitive or requires duplication. This redundancy not only hampers efficiency but also leads to increased costs.

• The Waterfall methodology is not flexible, and it is not suitable for projects that require frequent changes.

• While documentation is crucial for ensuring completeness, an excessive amount can create challenges in the software development process, making it impractical to build and test the software.

• In the Waterfall approach, the software development stage typically occurs late in the project timeline. This introduces significant risks, such as potential technological obsolescence. Additionally, software testing often begins only after the code is fully developed, irrespective of the expertise of analysts, designers, and developers. Testers inevitably uncover imperfections that need to be addressed. As the project progresses through its phases, the cost associated with resolving errors or issues in the project grows exponentially, also referred to as Boehm's law.

In the diagram, x represents a particular cost. So, 60–100x basically means that the cost can escalate by a factor of upto 100 if a bug is found after the product is released.

The Agile framework

The Agile framework is an iterative approach to project management. It is often used for projects that are complex, uncertain, and require frequent changes in direction. In the Agile framework, the project is divided into small, manageable chunks, each of which is completed in a short period of time. These chunks are known as sprints, and the duration of sprints is usually between one to four weeks.

The Agile manifesto

Let's have a look at the Agile manifesto, which was drafted in 2001.

Individuals and interactions over processes and tools

Agile values the importance of human communication and collaboration. The emphasis is on effective teamwork and communication, which are crucial for project success, thus placing more value on people than on rigid processes or tools.

Working software over comprehensive documentation

Agile emphasizes the importance of delivering a functional product rather than extensive documentation. While documentation is still valued, the main focus is on creating working software that provides value to the customer.

Customer collaboration over contract negotiation

Agile promotes close collaboration with the customer throughout the development process. By involving the customer in decision-making and seeking their feedback, Agile teams can better align their work with customer needs and expectations.

Responding to change over following a plan

Agile acknowledges that requirements and circumstances can change over time. It encourages teams to be flexible and responsive, allowing for adaptation and adjustment to deliver the best possible outcome, even if it means deviating from the initial plan.

Methodologies in the Agile framework

There are different methodologies within the Agile framework, each with its own approach to project management and software development. Some of them are listed below:

• Scrum is an iterative and incremental Agile framework focused on managing complex projects. It focuses on collaboration, flexibility, and continuous improvement. Scrum divides the project into short iterations called sprints that typically last 1-4 weeks.

• Extreme programming is an Agile methodology that requires high-quality software development through collaboration and frequent feedback.

• Kanban is focused on visualizing and optimizing workflow. It originated from lean manufacturing principles and is widely used in software development.

• Crystal is designed for different project characteristics and team sizes. It emphasizes human interaction, communication, and frequent delivery. Crystal methods are lightweight and flexible, adapting to the needs of each project and team.

Let's take a look at advantages and disadvantages of the Agile framework.

Advantages

• The Agile framework is flexible, and it is suitable for projects that require frequent changes. The methodology allows the team to adapt to the changes and make changes in the project requirements.

• This framework encourages collaboration between team members, and it promotes open communication. The methodology helps the team to work together and deliver the project on time.

• The focus is on delivering value to the customer. The framework allows the team to deliver the project incrementally, and the customer can provide feedback at each stage of the project.

Disadvantages

• Agile methods are complex as they require a high level of skill and expertise from the team members.

• Documentation is not a focus of Agile methods, therefore it can become difficult to track the project progress.

• Because the requirements can keep on changing, it is difficult to estimate the project timeline and budget.

Choosing the right methodology

After discussion on both the advantages and disadvantages of both methodologies, we can summarize when to use the Waterfall model and when to use Agile in a table below:

Agile vs. Waterfall tools

When it comes to project management tools, the choice between Waterfall and Agile tools depends on the methodology being used. Waterfall tools are designed to support the linear, sequential approach to project management, while Agile tools are designed to support the iterative, flexible approach. Waterfall tools, such as Microsoft Project, are ideal for projects with a clearly defined scope and well-understood requirements. They provide a comprehensive set of tools for managing all aspects of the project, from scheduling to budgeting to resource allocation. However, they can be inflexible and difficult to adapt to changing circumstances.

Agile tools, such as Jira, are ideal for projects that are complex, uncertain, and require frequent changes in direction. They provide a flexible, iterative approach to project management, allowing teams to adapt to changing circumstances and requirements. However, they can be less structured and may require more frequent communication and collaboration among team members.

Wrapping up and next steps

Choosing the right project management methodology and tool depends on the nature and complexity of the project. Waterfall methodology and tools are best suited for projects with a clearly defined scope and well-understood requirements, while Agile methodology and tools are best suited for projects that are complex, uncertain, and require frequent changes in direction. Ultimately, the choice between Waterfall and Agile should be based on a careful analysis of the project requirements and the team's strengths and weaknesses.

While this blog provides a good starting point for Waterfall and Agile methods, please have a look at the various courses offered here at Educative: