Agile vs. Scrum vs. Waterfall: Which is Best for App Projects?

Agile, Scrum, and Waterfall are all project management methodologies that can be used during the app development process. Some of these are more rigid and structured, while others allow you to easily introduce new ideas or make changes in the middle of a project.

When beginning a new app project, you might ask which methodology is best for you. For example, what are the differences when comparing Agile vs. Scrum vs. Waterfall, and how can you tell which is best suited to your project?

Let's take an in-depth look at each of these methodologies to help you make an informed decision.

What Is Waterfall?

The waterfall project management methodology is less flexible and iterative than some of the other approaches we'll discuss later. Commonly used in engineering design, progress in this model generally flows in one direction (hence the name "waterfall") through each phase.

When you use the waterfall model, you are ordering each task in your project into linear sequential phases. Each of these phases relies on the previous phase's deliverables.

It was way back in 1956 that a waterfall-type model was discussed in relation to software engineering. During a presentation at the Symposium on Advanced Programming Methods for Digital Computers, Felix Torres and Herbert D. Bennington discussed the development nation's first air defense system, SAGE, and the waterfall-style phases they used.

Winston W. Royce is often cited as the first person to create a formal, detailed diagram of the waterfall method, though he didn't use the specific term in his 1970 paper.

His original model looked like this:

1. System and software requirements: Outlined in a product requirements document
2. Analysis: Creating the outcome of schema, models, and business rules
3. Design: Creating the architecture of the software
4. Coding: Software development, proving, and integration
5. Testing: Checking and debugging for defects in a systematic fashion
6. Operations: Complete systems installation, migration, maintenance, and support

In this model, you should only move on to the next phase when you have reviewed and verified the previous phase. There are many modified waterfall models that have been created since Royce's initial model.

Pros

Waterfall can be a good choice for simple projects that are unlikely to change in scope during development. It is easy to use because it is straightforward, linear, and rigid. This also allows for thorough and in-depth documentation.

Some of the major advantages of waterfall include:

• Simple to use and manage: When you use the waterfall method, you are following the same linear phase structure for every project you take on. This makes it simple to understand and use. Teams can use the waterfall method without any training or prior knowledge of the method. It's also easy to manage and control this model because it is so rigid– every phase dictates the deliverables that will emerge and allows for a review before moving on.
• Enforces discipline: Since there is a definite start and end point to each phase in waterfall, this method makes it very easy for teams, stakeholders, and customers to have a clear sense of the progress of the project. The risks of missing important deadlines are also reduced because all of the requirements and designs are determined before the coding phase begins.
• Demands in-depth documentation: You can better understand the logic that underlies all of the code when using a waterfall method because documentation is required for every phase. This also means that there is a paper trail that can be referred to by stakeholders or developers later on.

Cons

One of the reasons that software developers came up with a number of more lightweight methods in the 90s was because of the most apparent downside of the waterfall method: its inability to effectively deal with change.

You can't switch back and forth between phases in this method, no matter what happens.

Here are some of the primary drawbacks of using a waterfall method:

• Coding doesn't begin until late in the process: Stakeholders don't get to see any working software until several phases have already been completed due to the rigid nature of waterfall's phase structure.
• It doesn't deal well with change: If you want to add a feature, take a feature away, change the scope of the project, or make any other tweaks after the project begins, you'll find it very expensive and challenging to go back and make the fix.
• It can be difficult to gather accurate requirements: While it might seem like a good idea to get all of the requirements outlined early in the project, it's not usually as easy as it seems. It's common for clients to not have a clear sense of what they want from the get-go, and waterfall doesn't accommodate this reality.

What Is Agile?

Agile first became popular in 2001 thanks to the Manifesto for Agile Software Development. Several lightweight software development models were created during the 1990s in reaction to waterfall methods, the reason being that waterfall models were seen as overly planned, micromanaged, and regulated.

During this time, lightweight methods like RAD, UP, DSDM, Scrum, XP, and FFD were developed. Even though the Agile Manifesto came after the introduction of these various models, all of the aforementioned methods now fall under the umbrella of agile software development methods.

The authors of the Agile Manifesto clearly stated that they wanted to focus on the following in creating their new method:

• Individuals and interactions over processes and tools
• Working software over comprehensive documentation
• Customer collaboration over contract negotiation
• Responding to change by following a plan

There are twelve principles of Agile that are outlined in the manifesto:

1. Customer satisfaction is the highest priority, achieved through the "early and continuous delivery of valuable software."
2. Embracing requirement changes for the competitive advantage of the customer, even if it happens late in development.
3. Frequently deliver working software, giving preference to weeks over months.
4. Close cooperation and collaboration between developers and business people on a daily basis.
5. Projects should be built around individuals that are motivated and have the support they need so that customers can "trust them to get the job done."
6. Face-to-face conversation is the "most efficient and effective method of conveying information to and within a development team."
7. The primary measure of progress is working software.
8. Sustainable development is promoted by agile processes, allowing developers, sponsors, and users to maintain an indefinite constant pace.
9. Good design and technical excellence should receive continuous attention in order to enhance agility.
10. Simplicity is essential (referred to as "the art of maximizing the amount of work not done").
11. Self-organizing teams lead to the best architectures, designs, and requirements.
12. Teams should reflect on how to increase efficacy at regular intervals and then makes adjustments accordingly.

Agile software development focuses on product development with non-deterministic, non-linear, and dynamic characteristics, as well as complex systems. Rather than trying to create stable plans, predictions, and accurate estimates in the early stages of a project, agile development understands that both the requirements and design of the project will emerge as things progress.

The thinking here is that it isn't economically sound to create big up-front specifications at the beginning of a project. Instead of having a firm, unmoving method that can't react to the inevitable changes and obstacles that occur along the way, agile prioritizes iterative, adaptive, and evolutionary software development.

Pros

Focusing on speed, continuous improvement, and flexibility, agile evolved as a response to the linear and rigid methodology of waterfall.

Some of the major advantages of agile include:

• Embracing change: It's a lot easier to deal with changes with agile than with the waterfall method because of shorter planning cycles.
• Faster delivery: Teams can deliver a high-quality product faster because of the way that the project is broken down into manageable units, known as iterations.
• Allows customers to have a voice: During the development process, customers get to see the project progress, give feedback, and have a say over what the final product looks like.
• Works well for projects where the end goal is unknown: For projects where there isn't a clearly defined end goal, agile can work well because of its adaptability.
• Emphasizes strong team interactions: Focusing on the importance of frequent interactions within the team, increased accountability, and responsibility among team members are major pros of the agile method.
• Allows for continuous improvement: Through the agile method, projects are always open to continuous improvement through team member and user feedback.

Cons

Even though agile has a lot of advantages over the waterfall method, that doesn't mean it doesn't have its downsides. Here are some of the cons of the agile method:

• Requires a knowledgeable team: It's usually essential for agile teams to be highly skilled in a number of areas, including the specific agile methodology you're using.
• Can make it difficult to plan concretely: Agile is great because it is so flexible, but this can also make it difficult to set a concrete delivery date. This also means that the final product can end up being a lot different than the original vision.
• Requires a larger time commitment: Collaboration and active involvement are required as a part of the agile method, which is typically a lot more time-consuming than the waterfall method or other traditional approaches.
• Can lead to less comprehensive documentation: Because of the prioritization of working software over thorough documentation, teams might struggle to take the time to create the necessary documentation.

What Is Scrum?

Scrum has been used in a number of fields, including sales, marketing, research, and advanced technologies. However, it was primarily created with an emphasis on software development.

Designed to be used by teams of ten or fewer, Scrum instructs teams to break their work down into different goals that are able to be completed within "sprints." Sprints are time-limited iterations, usually about two weeks and no longer than one month.

A part of this method involved "daily scrums," which are meetings of fifteen minutes or less to assess progress. Two more meetings are held at the end of each sprint, one to review the work done for stakeholders and receive feedback and another to give the team a chance to reflect on their work and make improvements for the future.

The name "scrum" was chosen because of its implications for teamwork (referencing the rugby term describing a specific formation of the players.)

Scrum is a lightweight, incremental, and iterative framework intended for the development, delivery, and maintenance of complex software products. Rather than taking a sequential approach like the waterfall method, the scrum method focuses on daily face-to-face communication between all parties involved and self-organizing teams.

One of the primary ideas behind Scrum is that customers inherently change the scope of a project during its development. Another is that unpredictable challenges always crop up during the process.

Because of these two ideas, Scrum recognizes that a waterfall-type approach (where everything is planned out and predictive) is simply not suitable. Instead of trying to force a fixed system on an inherently changing process, the scrum method argues that any obstacles or changes should be embraced, accepted, and thoroughly analyzed to find the benefits hidden inside these seemingly inconvenient occurrences.

Pros

One of the most popular ways to implement an agile methodology, the benefits of Scrum include:

• More accountability on teams: Because of the focus on teamwork, everyone works together collaboratively in this method to accomplish what needs to be done in each sprint. Both independence and teamwork are essential here, and the combination can increase accountability.
• Flexibility when it comes to making changes: It's a lot easier to deal with changes using Scrum than with the waterfall method because of the short sprints and frequent opportunities for feedback. Features can easily be added to the next sprint, for example.
• More visibility and transparency: With the focus on quick, daily meetings and frequent communication, there is a lot less room for confusion and misunderstandings with Scrum than with other methods.
• Increased cost savings: Since the project is broken down into smaller chunks and there is frequent communication, mistakes can be corrected quickly and early on in the process, reducing the cost of fixing any issues that crop up.

Cons

Teams need to be committed and have quite a bit of experience in order to truly benefit from Scrum. Let's look at some of the cons of this project development method:

• Choosing the right Scrum Master is key: Scrum Masters aren't the same thing as a project manager and don't have authority over their team. Projects using the scrum method with the wrong Scrum Master (i.e., one that micromanages or tries to control the team) will most likely fail.
• Commitment and experience are required: Success with this method requires that the team is committed to the project and familiar with scrum principles.
• Scope creep is a risk: Because of their flexibility and lack of a specific end date, stakeholders can sometimes continuously request additional features and functions. This can create problematic scope creep.
• Inaccuracies can arise from poorly defined tasks: It's essential to define tasks well if you want to stay on track and within budget.

Agile Vs. Scrum Vs. Waterfall: Which Is Best For Your Project?

Which model is best for your next app project depends on your specific needs and circumstances– in short, there is no right answer when you're deciding between agile, Scrum, and waterfall. That being said, you will want to take the nature of the project, the delivery deadline, and the size of the team into account when making this decision.

You might choose the waterfall method due to its rigid rules and linear structure if you have a fixed budget, scope, and deadline. However, if you want to get the product out on the market quickly and then make changes based on customer feedback, you might prefer to go agile. The scrum method is a good agile model if you want to create quite a bit of structure for your team without sacrificing flexibility in the overall project development model.

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