Both are methodologies for executing projects with waterfall being the traditional one and agile the newer, more modern one.
This is another post in my project management fundamental series and we'll look at the two approaches, their differences, advantages and disadvantages.
Let's describe briefly the two concepts first.
Waterfall project management is about chunking the project into linear sequential phases, with each new phase beginning only when the prior phase has been completed. It's often used in construction.
Agile, on the other hand, is an iterative approach with less initial planning focusing on continuous releases and incorporating customer feedback with every iteration. It's often used in software development.
What Waterfall and Agile Look Like
Here's an image that visualises the difference of each method:
As you can see, each phase in waterfall starts after the previous one is complete, culminating in the big outcome. In agile, it's iterative and the outcomes build upon each other until the big end.
Waterfall project management relies a lot on detailed planning of time, resources, risks etc. at the start and documenting these before beginning to execute. Every phase is clearly defined and tracked. The client, whether internal or external to your organisation, knows what to expect as the outcome was agreed upon typically at the beginning with the project charter. But if something goes wrong, the needs and requirements change or testing is unsuccessful, it's difficult to remedy the success of the project and often very costly too. A retrospective is usually done at the very end of the entire project.
Agile breaks down the project into multiple independent iterations. These are not as detailed in planning as with waterfall and allow for more flexibility, testing and changing. The outcomes are delivered bit by bit to the customer seeking ongoing feedback. Agile uses sprints to complete iterations and then analyses how these went and what needs to improve for the next sprint.
Both approaches have their pros and cons and I think they have specific needs in different industries. As I said in the beginning, waterfall is great in construction and manufacturing where you do need this detailed planning at the start and heavy decision-making. It also works well if you're executing a marketing campaign. For software or smaller projects in organisations, agile is great.
When you try to decide what to use, think about what you're trying to achieve.
I've often had to work on process development as projects. Naturally, neither approaches would fit perfectly so I've often used a mix of both without the need to strictly follow Agile's scrum process with a scrum master etc. etc. but with the flexibility to adapt with time even though I'd set up a more of a linear, waterfall project plan at the start.
There's lots online about both topics. I am PMI certified with the waterfall approach as I did my certification in 2019 but from last year the PMI has been moving more and more towards agile.
As a project manager, you should build flexibility into how you execute your projects and choose from both worlds however suitable.
Lastly, I'll leave you with the advantages and disadvantages of both approaches to give you some final food for thought.
Pros and Cons of Waterfall and Agile Project Management [Infographic]
Do you use waterfall or agile project management?