Waterfall or agile project management methodology

Waterfall or agile project management methodology
Ivan Pavlov
December 12, 2019
Last updated: May 11, 2020

Waterfall and agile are two popular methods in the world of project management and these methodologies are often pinned against each other.

In this article, we’ll explore which of these approaches is better and compare and contrast the two models, with a focus on their advantages and disadvantages for different types of projects. This will help you determine which one will work better depending on your project’s specific needs, as well as things you’ll need to come to terms with when you commit to your chosen methodology.

So, let’s get right into it.

Waterfall project management definition

Waterfall project management

The waterfall method is a traditional project management approach and at its core, is perhaps the most straightforward way to manage projects.The reason that this is seen as a simple approach is that unlike other methods, the waterfall method employs a very linear and sequential methodology. A waterfall project can be separated into the following six discrete phases:

Phase 1: Requirements and analysis

In the first stage, the project manager collects and analyses all the necessary requirements and documents for the project.

Phase 2: Design

This involves designing project workflows and outlining everything that the project will need in order to be carried out according to the requirements laid out in the first stage.

Phase 3: Implementation

In this stage, the project is executed according to the design document, with a strict adherence to the procedures and timeframes that were agreed upon in previous stages.

Phase 4: Testing

The product/deliverables are tested to ensure they meet the requirements that the project laid out

Phase 5: Deployment or delivery

This denotes the launch of the product or service 

Phase 6: Maintenance

The product or service is monitored and maintained

The waterfall model is a very strict form of project management. Each phase must end before the next one can begin and there is no restarting a phase or going back to the one prior. The stages are exactly like a waterfall, with one stage reaching its completion and then “dropping off” for the next one to begin.

Waterfall project management works really well for projects that have very clear objectives and outputs – for example in construction, manufacturing or engineering. 

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Advantages of the waterfall model

So, what benefits can a waterfall model offer your project? 

  • Makes large projects manageable

First and foremost, it’s a great option for projects that require a lot of structure and order – for example, complex projects with a lot of tasks. The waterfall approach breaks everything down and provides a logical, straightforward model of the project that is easy to visualize and follow.

  • Helps team members stay focused and organized

The waterfall model can bring a lot of advantages for individuals team members working on the project. Its structure allows everyone to know what they’re doing at all times, and what common end goal they are working towards, which makes processes very defined and clear from the get-go.

  • Ensures deadlines are met

As it’s so methodical and structured, it’s great for staying on track and making sure tasks and the project as a whole meet deadlines.

Disadvantages of the waterfall model

On the other hand, the waterfall model is also:

  • Outdated

The waterfall model is has become a somewhat outdated approach and isn’t particularly progressive in comparison to other methodologies.

  • Rigid

Whilst its structure and methodological approach can be an advantage, a drawback to this can be that any changes are very difficult to implement. As everything is highly sequential and follows a strict order, there is little room for adjustments – which is quite problematic when something unexpected comes up that messes with deadlines.

  • Not for large projects

Though it can be useful for complex projects with multiple tasks, lengthy projects aren’t best suited to the Waterfall methodology. Most require a more nonsequential approach, with lots of going back and forth between tasks. Projects with a linear structure are much more rare, so this method is only really suitable for specific projects. 

Agile project management definition 

Agile project management

Agile project management is a modified and modernized version of the waterfall method and is one of the more popular choices for the majority of projects. The Guide to the Project Management Body of Knowledge highlights its key distinguishing characteristics and describes agile as a methodology that “facilitate[s] change and require[s] a high degree of ongoing stakeholder involvement”. The Agile Manifesto sums up the entire approach in 4 key values: 

  • Individuals and interactions over processes and tools

  • Working software over comprehensive documentation

  • Customer collaboration over contract negotiation

  • Responding to change over following a plan

Though agile’s focus is more on adaptability and responding to changes over following a linear structure, it does have a set of clear stages in its lifecycle, which are known as the following:

Stage 1: Envision

In this phase, the project team determines the overall vision of the project, what problems it aims to solve, as well as the product(s) that will be produced. 

Stage 2: Speculate

Agile isn’t as focused on setting a strict plan, but every project needs a sense of direction. In this phase, a project roadmap (complete with a timeline) is outlined, which will then guide team members to its completion.

Stage 3: Explore

Agile project management aims to break down the project into small chunks (often referred to as “sprints”) which are more manageable and easier to complete in a short space of time. In the explore stage, the team create a release plan and execute the project using this “sprint” approach.

While executing the project, team members continually explore better, more suitable alternatives to the current execution plan. 

Stage 4: Adapt

This phase runs simultaneously to the explore stage outlined above. In each iteration, teams gather feedback and use this to modify and adapt the product and the project execution method.

Stage 5: Close

The project team delivers the final product(s) and ensures that it meets the requirements. Feedback is gathered and analyzed for future projects.

The agile approach works best for projects that focus on continuous delivery and improvement of the product(s) – for example, app and software development. 

Advantages of agile project management

The agile approach has a number of important strengths, namely: 

  • It’s flexible and realistic

First of all, thanks to its segmented methodology, this enables teams to adopt a more flexible and adaptable response to projects. It encourages “responding to change over following a plan” – and as circumstances are highly likely to change as the project progresses, this is a much more realistic way of approaching things.

  • There’s more chance of success

Building on the point above, adapting to change also means that the project is more likely to be successful – issues are spotted early on and fixed.

  • It encourages constant improvement

Teams evaluate what does/doesn’t work at each small stage, which helps them continually improve as the project progresses. This also means that they work more effectively in future projects, as they’re more used to adapting and improving their strategy.

Disadvantages of agile project management

Though agile is a fantastic methodology when it comes to project management, it definitely has some drawbacks that need to be kept in mind:

  • It’s more time-consuming

Due to the fact that agile allows for changes and revisions, and there may be a lot of going back and forth between stages, this means that projects using this methodology will require more time and commitment

  • Less organized

Though agile projects are organized, in comparison to waterfall, there is much less emphasis on order. Agile doesn’t focus as much on documentation which can result in more confusion and misunderstandings between team members

  • Possible scope creep

As the project is constantly changing and evolving and often doesn’t start with a clearly defined end-goal (definitely not as defined as it should be in a waterfall project), this greatly increases the likelihood of scope creep. New requirements are often added during the course of the project.

The difference between waterfall and agile project management 

As you may have already discovered, agile and waterfall have very different approaches when it comes to project management.

Here is a breakdown of their key differences: 



More structured. Has a fixed plan from A to B.

Less structured in comparison. Has a plan, but this can be (and is) modified throughout the project lifecycle.

Employs a logical, sequential structure in which each stage must be completed before the next one can begin. Features discrete, non-overlapping stages.

Breaks down the project into small increments, which are often referred to as sprints. Stages can overlap.

Best for projects that aren’t expected to have any changes along the way.

Works better for projects that will change as they progress.

Once a step has been completed, there is no going back to the previous stage.

Allows teams to go back and forth between stages if necessary.

A lot of importance is given to documentation and paperwork.

Most of the attention is on the product and deliverables.

Doesn’t place a strong emphasis on communication.

Communication and feedback are very important.

Product development and testing are two separate stages, with the former preceding the latter.

Development and testing occur simultaneously.

Doesn’t require customer feedback or participation.

High level of customer involvement and feedback. 

Agile or waterfall methodology in project management: which should you use? 

Generally, both models have strong advantages as well as significant limitations, so which one you use is highly dependent on the type of project.

There are differing opinions when it comes to which strategy works best for longer or shorter projects, but generally, waterfall is considered to be better suited for shorter projects, whereas agile is the more optimal choice for longer projects. This is mainly down to the fact that waterfall is linear, and does not allow for modifications and changes, which increases the risk of failure if the project stretches over a lengthy period of time. Agile breaks projects down into phases, making the long projects more manageable.

Another aspect to consider is how likely your project is to change or run into challenges. Waterfall works best for projects with very clear outcomes that won’t need a lot of changes and aren’t likely to have lots of issues as it progresses – for example, when building something such as a car. Agile, on the other hand, works well for projects that expect a lot of changes and modifications throughout their lifecycle, such as when developing a software product – the iterations allow new features to be delivered continuously throughout the project.

Whichever you choose – keep in mind that both models do have limitations. An ideal solution would be to use the Agile-Waterfall hybrid, which combines the strengths of both approaches: the order and organization of waterfall, and the versatility of the agile model. 

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