Agile vs Waterfall: the Difference Between Methodologies

One of the most challenging and eternal questions in project management is “What way of organizing the work of software development to choose?” This is about development methodologies.

This topic gets a lot of discussions and hot debates as every software development project starts with the selection of implementation methods. 

There are two basic and most popular methods of managing projects in the modern software development industry:

• Waterfall is the first of them. It can be also called the traditional method of software development. 
• Agile is the second one. This specific type of Rapid Application Development is newer than Waterfall (it originated in the 2000s) and it is typically implemented with Scrum or Kanban.

What is the Difference Between Waterfall and Agile Methods? Both of these methods are usable and mature. The selection of a certain methodology depends on the particular project and the company that performs it. 

In this article, we define the main advantages and disadvantages of each approach to software development and offer a quick differentiation of both methodologies, which we have posted in a handy infographic at the end of the post. So, let get started!

If you have no time for details, here’s a brief Agile vs Waterfall comparison table:

Quick Agile and Waterfall comparison table

If you want to get some details, it worth starting with the basics.

Introducing the Waterfall Methodology

Waterfall means a linear approach to development. The traditional method is based on strict planning and performing the plan step by step. It is usually used by companies with a hierarchical structure. 

The sequence of events according to this method looks that:

1. Gathering and documenting requirements. During the next stages of work, all the actions will be conducted based on this documentation. The customer is involved in the project performance only at the first and the last stage.
2. Design. At this stage, the developers try to find a suitable form to meet all the customer’s requirements.
3. Code and unit test. The main task of this stage is to test codes and unites.
4. After that, the system and user acceptance are tested.
5. Fixing issues.
6. Delivering the finished product to the customer.

All these events in a Waterfall development project represent a distinct stage of software development. Typically, every stage finishes before the next one can begin. Additionally, there is a stage-gate between each. For example, a client must review and approve requirements before design can begin.

Waterfall model advantages

• This is a clear framework and one of the easiest models to manage. You get a clear understanding of your project timeline and deliverables before the project begins. The project scope is agreed upon by the development team and the clients in advance.
• It provides faster project delivery.
• The method works well for smaller size projects (with easily understandable requirements).
• Planning and designing look straightforward because developers and customers can agree on what will be delivered early in the development lifecycle.
• It offers well-documented processes and results. Every project phase is documented in detail to eliminate misunderstandings and shortcuts.
• Progress is more easily measured, as the full scope of the work is known in advance.
• It provides a shared load. Depending on the phase, every team member can focus on other aspects of their work.
• Waterfall is a hands-off approach. After the initial design and project plan is in place, there is little requirement for ongoing customer presence until the review phase.
• It looks rather beneficial to manage dependencies.
• It is easily adaptable for shifting teams.

Waterfall disadvantages

As you can guess, such an approach has lots of disadvantages. Here’re some of them:

• Waterfall looks not ideal for large-size projects.
• The method is less effective if the requirement is not clear at the very beginning.
• It is rather difficult to move back to makes changes in the previous stages.
• The testing process starts once development is over. So, there is a high chance of bugs to be found later in development where they are expensive to fix.
• After the project is finished, the customer can be disappointed with its results, because all the work on a project was based on the initial documentation and the result may not meet the customer’s expectations.
• It provides less customer involvement. Some clients will want more involvement as the project proceeds.

Introducing the Agile Methodology

Agile is an iterative approach to development that emphasizes the rapid delivery of an application in complete functional components. All time here is time-boxed into phases called sprints. Every sprint has a defined duration with a running list of deliverables, planned at the start of the sprint. Deliverables are prioritized by business value as determined by the customer.

In this methodology, development, and testing activities are concurrent (unlike in Waterfall). Agile transformation allows more communication between developers, managers, testers, and customers.

The difference of Agile in the comparison Agile vs Waterfall is that the Waterfall approach values planning ahead, while Agile values adaptability and involvement.

There are different flows of Agile development that share some basic similarities:

• XP (Extreme Programming)
• Kanban
• Scrum
• Lean software development
• Agile Unified Process

The approach has two major elements: teamwork and time. Agile breaks the project into individual deliverable pieces instead of creating a timeline for one large project.

What are the core principles of Agile development?

There are some core principles that any Agile development project follows:

• Adaptability. The ability to change design, requirements, architecture, and deliverables are very important in Agile.
• Lean development. Agile software development values making the end product as simple as possible.
• Customer involvement. Agile development requires close collaboration between the customer and the development team.
• Teamwork. Agile values teamwork almost above all else. The aim of the teams is to continually assess how they can become more effective and adjust projects as they go.
• Time. The methodology breaks projects into very small units of time. These are the time-boxed sprints.
• Sustainability. Agile places value on setting a sustainable pace for software development instead of pushing for faster deadlines in exchange for an unfinished project.
• Testing. Agile insists on testing through every phase of the project (unlike Waterfall approaches where there is a distinct testing phase).

Agile method advantages

• The Agile methodology is focused on the client process. It makes sure that the client is continuously involved in every stage. Customers have an opportunity to see the work being delivered and to make decisions and changes throughout development.
• Customers have a b sense of ownership by working extensively and directly with the project team throughout the project.
• Agile development is often more user-focused. This is the result of more and frequent direction from the customer.
• It guarantees that the quality of the development is clearly maintained.
• The Agile offshore development process is completely based on incremental progress.
• Agile teams are extremely and self-organized and motivated. This provides better results for development projects.
• The clients know exactly what is complete and what is not that decreases risks in the development process.
• The deliverables are flexible. Stakeholders can set deliverables by order of importance.
• It offers higher quality and user-friendly products. Clients can provide feedback after each sprint, so the products developed using Agile often end up being very user-friendly.

Agile disadvantages

• Agile is not useful for small development projects.
• It provides intense commitment. Unlike the traditional approach, Agile development only works well when the entire development team is committed to the project for the duration.
• Agile projects can easily go off track if project managers are not sure what outcome they want.
• Agile meetings require the presence of an expert to take important decisions.
• Communication issues. Agile requires a high level of collaboration, so development projects using this methodology will also require a high level of communication.
• The cost of implementing Agile is a little more compared to other methodologies.
• The high degree of customer involvement may present problems for some clients who may not have the time or interest in this type of participation.
• The close working relationships in Agile requires working in the same physical space, which is not always possible.

Detailed Differences Between Agile and Waterfall Models

Making the Choice Between Agile and Waterfall

Your ultimate choice between Agile vs Waterfall methodologies depends much on several factors.

Waterfall may be the best choice if there is no (or limited) access to a customer to provide constant feedback. It will also suit projects with a dispersed team, fixed budget, and scope.

Agile looks preferable for more complex and larger projects, where there is easy access to customer feedback. Its flexibility makes Agile more suitable for projects with constantly changing requirements.

The main difference between Agile and Waterfall methodology is that the Agile approach to software development has no strict structure

The way of document management is one more distinction between Agile and Waterfall methodology. Usually, Agile teams do not have any documents at all. There is no need for documents because the customer can see the progress of work at any time he wants.

The different way of teamwork is what we see first when we compare and contrast Agile and Waterfall. There is no strict structure in the Agile teams. All their members are interchangeable, so the work goes faster. There is also no need for project managers because the projects are managed by the whole team.

Agile approach is aimed at faster implementation of any project. The work of Agile teams is subdivided into 2 – 4 week-long sprints and the customer can see its intermediate result at the end of any of them.

Generally, the Agile approach to software development is more flexible and in most cases, it meets the requirements of the customers and final users better. That is why it is more useful for most projects.

In recent years, Agile became the predominant product development methodology, being used by a large majority of development organizations.

Even developers still using the traditional approach tend to use a hybrid approach using both Agile and Waterfall. Despite the evident success of Agile, the Waterfall model is still a valid approach in certain circumstances.

No matter what methodology you choose, there is a great selection of PM tools available to you.

Project Management Software for Waterfall and Agile

Today many modern PM solutions propose powerful functionality to manage both Waterfall and Agile projects. Hygger.io is a wonderful example.

With roadmaps based on Gantt charts, templates, task lists, reporting tools, and more, it seems like a great solution for Waterfall management. Hygger allows to assign tasks to team members and create dependencies between tasks.

Agile admirers enjoy convenient Kanban/ Scrum boards with Swimlanes and WIP limits, subtasks, prioritization and scoring frameworks, etc.

Conclusion

Agile and Waterfall software development methodologies are rather different and good in their respective way.

To summarize this post, let’s define key differences and highlight them here:

• Waterfall suits projects with well-defined requirements where no changes are expected. Agile looks best where there is a higher chance of frequent requirement changes.
• Waterfall is easy to manage and a sequential approach. Agile is very flexible and allows to make changes in any phase.
• In Agile, project requirements can change frequently. In Waterfall, it is defined only once by the business analyst.
• Agile performs testing concurrently with software development whereas in Waterfall methodology testing comes after the build stage.
• In an Agile project’s description, details can be altered anytime, which is not possible in Waterfall.

What software development methodology do you prefer? Which method do you prefer in the battle of Agile vs Waterfall? Feel free to share your experience below.

*the pictures used are from unsplash.com and pexels.com (A. Beliaikin)