Agile vs Waterfall: A Few Resources to Help You Choose
In this corner, we have waterfall. Long the champion of the sequential approach through the typical development phases such as design, development, testing, deployment, and maintenance. Developers work through each phase in order, like a "waterfall" cascading down over the rocks.
And in this corner, we have agile. Sometimes you'll see it as big Agile with a capital A, other times as little agile with a lowercase a. Agile is certainly a livelier approach, taking an adaptive and flexible role in the planning, development, delivery, and continuous updating stages. Instead of doing one phase at a time, teams work on all phases, all the time.
So is it one or the other? Should you use the older waterfall approach or the more adaptive agile approach? As you’ll see from some of the expert analysis we've gleaned from the blogosphere, the prevailing attitudes and preferences lean heavily toward agile.
Every development project is different. Every client—even internal clients—have different requirements. Few get this concept as well as the folks at The Digital Project Manager. This site has a deep, profound analysis to help you determine the best approach for particular projects, not really taking a side, but providing thoughtful explanation of the determining factors. Deeper into her analysis, the writer Suzanna Haworth dives right in:
"What should influence your decision on which methodology to apply to a project? Until you know what the project is and other influencing factors, you’re not going to be able to decide which is best suited. Some (or all) of these factors should be taken into account when looking at methodologies:
- Size of the project
- Organizational factors
- Clients or stakeholders, external and internal
What projects can Waterfall be suited to? Waterfall projects are:
- Projects where you’re working with other organizations or remote workers
- Projects with a fixed scope, time and budget
- Smaller, well-defined and simpler projects
- Projects with an absent client.
- What projects can Agile be suited to?
Agile projects are:
- Projects where your organization is responsible for the whole process
- Projects with scope for changing requirements
- Larger, undefined, complex projects
- Projects with an involved client.
But do organizations really take into account all of these factors? What, or who, actually decides a process? Possibly the main thing that influences a chosen methodology is existing processes. Your organization’s current processes are likely to determine how you run your project—whatever that project is. It’s the classic one-size-fits-all approach. Given that each project has different needs, and can differ quite widely in influencing factors, this isn’t the best way to run every project at your organization."
At this point, Haworth admits she has been sitting on the fence, but then she does have to agree agile is better suited for modern digital projects. "Both methodologies...have benefits in their own right. But if we're living in an ideal world, the Agile approach does suit pure digital projects more. All the principles do seem to fit the digital landscape, where evolving needs and change are present throughout all projects." There you have it.
Approaching each step in the development phase individually has it benefits and its drawbacks. This affects how to deal with mistakes and subsequent corrections, and how quickly you can resolve them or expensive it becomes to do so. Agile Nutshell gives us a concise, graphic overview of how these phases flow from one to the other, and how to best navigate them with both methodologies. Post author Jonathan Rasmusson takes us through the grid:
"Traditional waterfall treats analysis, design, coding, and testing as discrete phases in a software project. This worked ok when the cost of change was high. But now that it's low it hurts us in a couple of ways.
- Poor quality: First off, when the project starts to run out of time and money, testing is the only phase left. This means good projects are forced to cut testing short and quality suffers.
- Poor visibility: Secondly, because working software isn't produced until the end of the project, you never really know where you are on a Waterfall project. That last 20 percent of the project always seems to take 80 percent of the time.
- Too risky: Thirdly you've got schedule risk because you never know if you are going to make it until the end. You've got technical risk because you don't actually get to test your design or architecture until late in the project. And you've got product risk because don't even know if you are building the right until it's too late to make any changes.
- Can't handle change: And finally, most importantly, it's just not a great way for handling change.
Instead of treating these as fixed stages, Agilists believe these are continuous activities. By doing them continuously:
- Quality improves because testing starts from day one.
- Visibility improves because you are 1/2 way through the project when you have built 1/2 the features.
- Risk is reduced because you are getting feedback early.
- Customers are happy because they can make changes without paying exorbitant costs."
Clearly, Agile Nutshell is a fan of agile over waterfall, and with that compelling argument it's difficult to disagree.
You would expect to find some sage advice on choosing the best development methodology from a place like the Project Management Institute. And indeed, the PMI site does not disappoint. This session was presented at a conference in 2012 but is still germane today, focusing on selecting a development methodology best suited for large-scale ERP projects:
- "Have you ever wondered how to deliver your project quicker and realize business value sooner from your ERP implementations?
- Have you ever wondered how to remove all of the "ceremony" of the implementation process and the "waste" involved with an ERP implementation while preserving the integrity of the delivered ERP package methodology?
- Have you ever wondered if there was a way to be flexible enough during ERP implementations, and that changing business requirements could be provided to a project team mid-implementation, without significantly affecting the overall cost and schedule?
- Have you ever wondered how to improve the efficiency and productivity of your existing ERP teams by doing 'more with less' in today's economy?
These are common questions that are asked when discussing how to improve the implementation of ERP projects. Consideration of Lean concepts and agile techniques to accelerate the time to delivery and the realization of benefits is becoming more prevalent. Project managers are challenging the ways they have been traditionally implementing projects and are seeking new approaches. However, there are many considerations in determining the right approach."
Check out the full presentation, in which the authors discuss the key determining factors to consider when deciding whether a particular project is better suited for agile or waterfall.
Posted by Lafe Low on 01/30/2018 at 2:28 PM