Project Management Methodologies – Waterfall vs Agile

The first and most probably one of the most crucial tasks of a project manager is to choose the most appropriate methodology for each project. Lately, the choice comes down to Waterfall VS Agile. Each of them has its advantages and disadvantages. We will look closely at each of them, the key differences between them, and determine when it is better to use Agile and when is Waterfall more suitable.

What are Agile and Waterfall methodologies?

Waterfall and Agile are the two most popular project management methodologies.

Waterfall is a traditional approach to software development projects. Sometimes it is also called Liner Sequential Life Cycle Model. As the name suggests, it follows a linear, sequential order. While using this model, the team works on one phase of development and moves to the next stage only after completing the first one.
The agile methodology follows an incremental approach instead of a sequential design process. The team works on small modules that include sprints. Tests are run at the end of every sprint.

Before we decide between Waterfall methodology VS Agile, let's take a closer look at them and their pros and cons.

How does Agile methodology work?

Agile methodology focuses on speed. It aims to provide rapid and continuous delivery of a product to the customer. The Agile methodology follows an incremental approach - software development is iterating down into small phases - Sprints. Each sprint comes with small deliverables.

Once the team finishes working on each sprint, the project manager reviews and evaluates the priorities, and testing begins. Based on the results and evaluation, PM plans the next steps of the project. It creates a space for more flexibility. In case there is a need for change, the team can adapt easily. Due to this, Agile is suitable for larger projects, where uncertainty and changes are anticipated.

With Agile methodology, it is easier to make changes in the initial planning, add features or make change requests during the development process. The client is involved in the project and can see the results as early as possible, while the project manager can constantly gather feedback.

Advantages of Agile methodology

Adjustable, allows PMs to make changes after the initial planning. It is easy to add features and make change requests.
PM re-evaluates priorities after each sprint, which helps to maintain the quality of the development.
The client is involved at every stage of the development.
Software is tested during the stage of development, and it is easy to find and fix bugs.

Disadvantages of Agile Methodology

Overall progress is hard to measure since the scope of the project is not clear.
There is a lack of clarity and understanding of the overall picture of the project. It leads to the piecemeal effect, a development phenomenon that can occur as pieces of code are written and added to an application where they may or may not fit well.
The degree of customer involvement may be a problem for some customers.

How does Waterfall methodology work?

Waterfall is a consequential methodology. It describes a development method that is linear and sequential. The development has distinct goals, and each of the steps is clear.

Once the team finishes working on one phase of the project, the development process moves to the next phase, and there is no turning back. We could compare this model to the real waterfall. When the water starts its journey down the rocks, we know it will not be coming back.

The project manager defines tasks upon in advance and communicates them to the client. The customer always knows what to expect, and planning is easily achievable.

Advantages of Waterfall Methodology

Planning is straightforward, and the customer always knows what to expect.
After the scope and task specification stage, this model does not require client involvement.
As the scope of the project is clear, it is easy to measure the progress.
There is clarity and understanding of the overall picture of the project.

Disadvantages of Waterfall Methodology

The waterfall model is not very flexible, it is not easy to make the changes to the previous stages.
The methodology relies heavily on initial requirements. If there is a requirement error, a change is hard to implement.
Testing starts when the development stage is over, thus detecting bugs can create more issues.
The customer is not able to see the product until the end of the project.

As you can see, both models have advantages and disadvantages. One is not ultimately better than another, and the choice between the Waterfall model VS Agile model depends on the project requirements.

The difference between Agile and Waterfall methodologies

There are few major differences between Agile and Waterfall methodologies. They have a different approach to the client, team, definition of scope, planning, development, and testing process. These differences do not make one model better than another. For example, Agile methodology requires the client's frequent involvement in the development process, while with the Waterfall model the customer takes part only in the first stages. For some customers, one might be more suitable than another. Likewise, if the project scope is very well defined in detail there might not be any need for the client's involvement. There are a few other differences to consider.

Agile VS Waterfall

Agile

Waterfall

The client is actively involved through the whole development process

The client is involved only at the milestones

Follows incremental approach

Follows sequential design process

Is very flexible and welcomes changes, but it might increase the cost of software development or change the timeline (Sometimes both)

Is not flexible and can be rigid when it comes to making change requests or adding features

During the Agile development, it is expected that requirements will evolve and change

In the Waterfall method requirements are strictly defined at the beginning of the project

Testing happens simultaneously and it is easy to detect and fix bugs at an early stage

Testing is run after the development. Bugs stay in the system longer, which can hinder the development process

When should you use Agile VS Waterfall project management models?

As mentioned, the choice between Agile VS Waterfall project management models depends on the project specifications.

When should you use Agile methodology?

The agile model works best with big projects that include significant software development and some requirements might change over time.
When the project scope is unclear and unlike to remain stable.
The project has a high degree of complexity and uniqueness.
The project requires regular, ongoing development of upgrades and updates.
The customer has difficulties defining the requirements and is likely to change the scope of the project
To achieve more visibility and low-risk management.
To ensure the development of the right product

When should you use Waterfall Methodology?

The Waterfall model works the best for the projects that do not require frequent involvement from the client's side.
For better tracking and measurement of the progress as the scope is known and agreed upon.
In order to have better resource allocation and planning
When you have a clear picture of what the final results should be.
If the project scope is well-defined and you do not anticipate changes in requirements.
When strict documentation is required.
The Waterfall model is suitable for short and clear projects.

Waterfall methodology vs Agile - Which one is better?

There is no clear answer to which one is the best project management methodology. The question is which one is suitable for your project?

The agile methodology works best when the project is big, complex, or unique and there are no strict specifications. The Waterfall model is the best for shorter projects that are very well defined and there are no changes anticipated.

Based on the style, advantages and disadvantages, and the differences between Agile and Waterfall, you can choose which one suits best your project and business needs.

Written by: Flat Rock Technology Team on July 21, 2016

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