Waterfall vs Agile: What’s the difference?

As your organization grows, you’ll need a way to keep everyone on the same page. In other words, you’ll need a project management strategy. In software development, there are two primary project management methods: Agile and waterfall. 

In this article, we’ll break down the differences between Agile and waterfall and the pros and cons of each. Remember, there is no “right” project management strategy for you and your team—you might use the Agile method for some projects and the waterfall method for others. Keep reading to learn how to pick the right method for each of your projects!

What is Agile methodology?

The Agile methodology is an approach to software development that emphasizes flexibility, efficiency, and the rapid delivery of a product. Cross-functional teams collaborate to continually improve and iterate. It’s built on four core values and 12 core principles outlined in the Agile Manifesto.

People often mistake Agile methodology for a step-by-step process for developing a product. But the Agile methodology is a philosophy—a way of approaching a project. Several frameworks and methods fall under the Agile umbrella (such as Kanban and Scrum). 

How Agile methodology works

Agile frameworks are all built around the sprint—a short, pre-defined period of time for achieving a set of deliverables. Typically, sprints are two weeks long, but you can change this based on your team’s needs.

At the beginning of each sprint, your team will decide on a set of deliverables you’d like to complete. As the project unfolds, your team should maintain constant communication with other stakeholders to reprioritize and adjust deliverables as needed.

In each Agile methodology, coding and testing are not broken into separate phases. Both happen during each sprint. The goal is to deliver a working product, not a perfect product. In subsequent sprints, you can improve the software iteratively.

Benefits of Agile methodology

There are many advantages to the Agile methodology. Here are three key benefits to consider: 

Collaboration and stakeholder engagement

Throughout each sprint, the development team, client, and other stakeholders discuss the product and deliverables. This frequent communication allows developers to integrate feedback into the product quickly, keeping the client informed and satisfied, and resulting in a better finished product.

Flexibility and adaptability

Because Agile methodology is an iterative approach, you can adjust the software to meet changing demands throughout the development process. 

High-quality products

Traditional software development strategies are broken into clear phases: Code first, then test. While this approach has its benefits, you might reach the testing phase only to realize you have a low-quality product. Agile methodology integrates coding and testing into each sprint, so you know exactly where the product is at. Plus, with each sprint, you’re improving it!

Disadvantages of Agile methodology

For all its strengths, Agile methodology also has its weaknesses. Here are some disadvantages to keep in mind:

Limited in scope 

To really see the benefits of Agile methodology, a project needs to last several sprints. For this reason, it’s best suited for mid- to large-scale projects. For a short-term project, a more linear approach is often best. 

Requires communication

Agile methodology requires extensive communication among team members, stakeholders, and the customer. If your team tends to struggle with collaboration or you can’t commit to the time needed for this level of communication, Agile might not be the best fit.

High cost

Because Agile methodology operates in two-week sprints, it can often be difficult to create an overall timeline. To handle delays and unforeseen obstacles, you might need to add additional sprints to the project life cycle. This means more time and more money. 

What is waterfall methodology?

If I asked you to describe a traditional software development strategy, you’d probably land on something close to the waterfall methodology. Whereas Agile is an iterative approach, the waterfall method is linear. Development is broken into distinct phases—before moving on to a new phase, you must complete the current one and have your work signed off by a supervisor. 

Though the exact phases vary from project to project and team to team, the overall structure typically looks something like this: 

• Phase 1: Conception. What type of software will you be building? The client will likely determine this.

• Phase 2: Analysis. What are the technical requirements of your project? These could include features, functionality, etc.

• Phase 3: Design. How will you achieve those requirements?

• Phase 4: Construction. It’s time to get coding!

• Phase 5: Testing. Once you finish coding, it’s time to see if you were successful. Does the final product meet the requirements?

Benefits of waterfall methodology

It’s tempting to assume that Agile methodology is superior because it’s more flexible, but that’s not always the case. Flexibility can lead to uncertainty. In some situations, the rigidity of the waterfall methodology can be just what you need. Let’s take a look at some of the strengths of the waterfall method:

Clear timeline and expectations

Because the waterfall method is a linear approach to software development, it’s much easier to accurately predict the duration and cost of a project before you begin.

Leaves room for other projects

Agile software development works best if each team member is fully committed to their project. Sprints are too short to allow team members to work on other projects. With the waterfall approach, team members can often split their attention across multiple projects.

Less customer involvement

Depending on how your team prefers to work, this could be an advantage or a disadvantage. If your developers are independent, less customer involvement means more room for them to get things done.

Disadvantages of waterfall methodology

Here are some of the cons of using waterfall: 

Less flexibility

In the waterfall approach, product requirements and specifications are defined before coding begins. This means that once development starts, it’s hard to implement any changes to those requirements. 

Late feedback

The linear structure of the waterfall method saves feedback for the end, after coding and testing have been completed. If the customer is unhappy, you may have to make substantial changes to the product. These changes will take more time and cost more money.

Limited in scope

Waterfall is not effective for longer projects. Delayed feedback increases the risk of expensive rework if the final deliverable misses the mark on either functionality or customer expectations. 

Key differences between waterfall vs. Agile methodology

At this point, you should have a good sense of the waterfall and Agile methodologies and the pros and cons of each. But let’s take a closer look at some of the key differences and how those differences impact your team:

Project scope

If your team uses the waterfall approach, the project's scope is determined in advance. This takes rigorous planning but gives you a better sense of the duration of your project and the resources needed to complete it. 

With Agile software development, you should also have some sense of a project’s scope before you begin. Here’s the difference: The scope can change before you complete the project. If a customer decides they want additional features, your team can add sprints to implement those changes. This flexibility can help your team deliver a great product, but it’s difficult to accurately predict a project's duration, scope, and cost.

Team

The methodology you choose determines not only how you develop a product, but also how your team operates and interacts with stakeholders. The waterfall method allows your team to take a hands-off approach. The customer is involved primarily at the beginning and end of the project’s life cycle—everything in between is up to your team. Plan meetings with team members as needed, but communication might be relatively sparse. 

Agile, on the other hand, requires full commitment from each team member. There’s no room for developers to be working on multiple projects. Your team should hold Agile meetings daily and update the customer at least once per sprint. 

Feature prioritization

In the waterfall approach, product features are determined in the analysis phase before development begins. All features are prioritized equally—they just need to be finished before the testing phase begins. 

Agile software development offers greater flexibility. If a customer decides they don’t want a feature, no problem—just send it to the bottom of the stack. Similarly, if a new feature is introduced or an existing one is reprioritized, you can address those changes in the next sprint. 

Choosing between Agile and waterfall

For small-scale projects with clearly defined deliverables (anything under a month), the waterfall method can’t go wrong. The customer knows what they want, and you know how to give it to them. It should be fairly straightforward.

If you think there’s a chance requirements may change, consider Agile instead. For these sorts of longer, more unpredictable projects, the product owner and customer should both be heavily involved. 

At the end of the day, it’s all about your organizational needs. Each method has its strengths and weaknesses—it’s up to you to decide which is best!

Agile-waterfall hybrid method

The Agile-waterfall hybrid incorporates the best of both methods. Because Agile is more of a philosophy, it can be applied to a rigid waterfall methodology. It will be up to you and your organization to determine the best hybrid solution for your team, but here are a few possible scenarios.

Possible Agile-waterfall hybrid combos

• Use the Agile method on an enterprise level while using waterfall for requirements, design, and implementation.

• Use the Agile approach at a project level, but use waterfall at the organization level. 

• Use the waterfall methodology at both the project and enterprise level, but use the Agile method for individual teams. 

• Use the waterfall methodology at both the team and enterprise levels, but select specific development phases that will use Agile techniques. 

It’s tempting to become a champion of one methodology, but it’s important to remember that the successful completion of the project takes top priority. The best methodology is the one that helps teams remain on task, produce a workable product, and stay within budget.