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Agile vs Waterfall Project Management

Agile came to the forefront in February 2001, when a group of seventeen software developers produced ‘The Agile Manifesto’, as an improvement upon the conventional waterfall in project management.

The Agile Manifesto is a set of values and principles that are followed by software developers in Agile project management. Agile has an incremental approach with quick adaptability to changes, where changes are welcome at any particular stage in the developmental phase.

Since the inception of Agile, there has been a lot of debate in the past two decades between the relevance and success rate of Waterfall and Agile. In this article, we will draw a comparison between waterfall vs agile to understand the key differences between them.

Before we look into the differences, it is essential to have a thorough understanding of how the two methodologies work:

What is Waterfall?

The Waterfall model in project management is a systematic linear approach where the project is divided into distinct phases and moves step by step towards the final release. The waterfall model does not make room for changes, and the release is tested only in the testing phase, which is the second last stage in the project’s lifecycle.

What is Agile?

Agile is a philosophy that drives an incremental model in project management that is adaptive and flexible, as compared to the Waterfall method. In an Agile project, several phases happen concurrently and change is incorporated as and when necessary to meet the stakeholder’s requirements and deliver valuable software.

Now that we have an understanding of the two approaches, we will look into the difference between Agile and Waterfall :

Agile vs Waterfall

Progress Visibility

In an Agile model, progress is measured in terms of the deliverables or working software produced in each sprint or iteration. Owing to the incremental approach of the Agile model, each release is an increment over the previous one and marks progress in the execution of the project. 

In the Waterfall method, progress can be measured when the deliverable is tested at the end of the delivery process. Progress is measured only through phases like requirements, design, development, and testing. As this method moves step by step and does not incorporate changes, the value of the software can only be assessed at a later stage. 


Agile is based on flexibility and adaptability. Changes are incorporated after each release to improve the product. Agile helps in the continuous delivery of valuable software, each release is thoroughly tested incrementally, and feedback is taken into consideration after each sprint or iteration to make changes.

The waterfall method does not allow for changes as in this model the project moves linearly from one step to another. The execution is planned at the beginning of the project and changes cannot be made midway. As a result, the Waterfall method is only suitable for teams with a clear idea of the project’s roadmap from start to end, which doesn’t need any change in the middle. 

Customer Involvement

In Agile, customer involvement is a fundamental part of the product development progress. There must be a continuous collaboration between the developers and the customer at each step, to ensure that the valuables are meeting the customer’s requirements. The frequency of customer interaction can be on a daily basis, at least at the end of every sprint/iteration. This enables a constant feedback loop in the system.

In the Waterfall method, expectations are set with the business owners at the beginning of the project, therefore there is minimum customer cooperation or scope for customer feedback during the process.


As Agile projects are welcoming to changes, adaptation and iteration, the budget estimated for each project is also tentative and flexible. It tends to increase depending on the changes required in each sprint. 

In the Waterfall method, the budget is fixed at the start of the project and there is hardly any room for change in the budget once the process has started.

Continuous Quality focus

Since the product is incrementally built-in Agile, every increment is expected to be working software. This drives quality in every increment, literally in every sprint or iteration. Defects injected into the system are immediately validated and fixed within the same sprint or iteration.

In a waterfall, since everything is built and then only testing starts, defects are found very late.

Product vs. Project thinking

Agile drives product thinking – the entire product development right from customer need to the customer using the system that satisfies his / her need. The team’s collaboration with customers enables product thinking for the entire team.

The waterfall is considered as more project management that has a shorter life span. 
The conclusion one can arrive at from an agile vs waterfall comparison table is that 

A waterfall is an approach that moves linearly with minimum customer communication. Hence it is ideal for projects that have a definite end goal with a definite schedule. 

On the other hand, though Agile is more adaptive and flexible, organizations that can involve customers in each sprint and have a broader timeframe and budget can opt for Agile methodologies. Agile is better suited for projects that need to adapt to changes fast and release to market faster.


Agile vs Waterfall Project Management

The key difference between agile and waterfall is that agile is a flexible approach to project management, whereas waterfall has a rigid linear structure.

What are the phases in Waterfall projects?

The phases in Waterfall projects are:

Compare the timeline of the agile vs waterfall method.

In Agile, the timeline is flexible as each sprint/iteration may increase with the changes incorporated. Product is built incrementally and enables more frequent delivery to customers. Hence, the timeline is defined based on customer needs.

The waterfall method has a rigid timeline as the entire project is mapped out at the beginning.

What are some of the drawbacks of the waterfall method?

Some of the potential drawbacks of the waterfall are as follows:
Minimum customer collaboration
Less to no room for incorporating changes
Last-minute testing leads to unpredictability and possible errors
Defects found late are  too expensive and delay the overall product release

What is the success rate of the Waterfall method vs agile?

According to a survey by Zippia, Agile projects have a success rate of 64% as compared to the waterfall method which has a success rate of 49%.

This content topic is related to CSM Certification, PMI-ACP, and other Agile Certifications.