The first and foremost decision to be made while building software is to finalize which development methodology to consider. While finalizing the models to take up, the two most prominent models are the Waterfall Methodology and the Agile Methodology. Here, we shall see the comparison between the two, Agile Vs. Waterfall Methodology. Hence, this article will help you choose a better fit for your requirement.
Software Development Life Cycle (SDLC)
Software Development Life Cycle (SDLC) is the process of designing, developing, and testing high-quality software. The SDLC aims to create the best quality software keeping in mind the customer’s expectations and deadlines. The process defines tasks that have to be performed at each step in the software development process.
The software development process makes sure that customer satisfaction is achieved. The project is completed within the required time frame and estimated cost.
Several Software Development Life Cycle Models are followed for successful software development processes. Every process has its series of steps that ensures its success.
The two most famous and popular SDLC models are:
- Waterfall Model
- Agile Model
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What is the Waterfall Model?
The Waterfall Methodology is the earliest Software Development Life Cycle approach to software development. The model is a collection of several phases, and each phase needs to be complete for the next phase to begin. More importantly, the next step depends on the deliverables of the previous step.
The project is broken down into several sequential phases. All those phases are followed in the Waterfall Model in a top-down approach. The process starts with the step of gathering requirements and goes up to the maintenance step.
The top-down approach of the Waterfall Model is called the Linear-Sequential Life Cycle Model.
How Does Waterfall Work?
In the Waterfall SDLC model, you must follow a rigid sequence; you only begin executing a phase after finishing the current one. The SDLC has only one direction, similar to a waterfall. The Waterfall model does not respond to a change and prioritizes comprehensive documentation over fast delivery of working software.
Linear-Sequential Life Cycle Model
The Waterfall Model approach is divided into six phases. The six phases are as follows:
Requirement Gathering
The first phase includes understanding the project requirements to be developed and documenting those requirements.
System Design
After the requirements have been specified, those requirements are studied, and system design is created. The model helps in preparing the overall system architecture.
Implementation
The input from the system design phase is used to develop a system in small programs or units. These units are tested for their functionality, and this is referred to as the unit testing.
Integration and Testing
The units developed in the Implementation phase are tested and then integrated into a system. After the integration process, the entire system is processed for any faults or failures.
Deployment
Once the functional and non-functional testing is complete; the project is deployed in the market or the customer environment.
Maintenance
After the deployment process, some issues come up on the client-side. The problems are fixed with patches, and then to enhance the project, better versions are released.
Pros of Waterfall Model
- The Waterfall Model is simple to use and easy to manage.
- No specialized training of project managers or employees is required to implement the Waterfall Model.
- The model applies to small projects so that the requirements can be easily identified.
- All the processes and results are well documented.
- The measurement of progress is easy since the beginning and end of the project are predefined.
- There are no changes in the final cost as it is calculated and fixed before beginning the project.
Cons of Waterfall Model
- Gathering all the requirements initially delays the project, and if all the requirements are not evident in the beginning, the overall process is less effective.
- Making changes in the previous phases is extremely difficult.
- It is not well suited for large size projects.
- The testing process starts only after the development phase is completed. This increases the chances of bugs found later in the development, and it becomes expensive to fix them.
- It isn’t easy to estimate the progress of the project within each phase.
- The model is an internal process, so customers have no space to become familiar with the process.
To curb all these cons of the Waterfall Model, the Agile Model came into consideration. Let's have a look at the basics of the Agile Model.
What is the Agile Model?
Agile Methodology is the practice that promotes continuous iteration of development and testing all through the software development lifecycle. The project is split into sprints, and every sprint has its defined duration with a list of planned deliverables.
Here, in the Agile Methodology, The work can be reviewed by the project team and the customer with the help of daily builds and sprint demos. The process ensures the rapid delivery of all the completely functional components of the project. The entire process has a very high level of customer involvement throughout the project.
There are five stages in the Agile Software Development Life Cycle that begins from concept building and goes up to the retirement process.
Stages of the Agile Life Cycle
The five stages of the Agile Life Cycle are as follows:
Initiation
The initiation or inception phase refers to the discussion of project vision and justification of ROI.
Planning
The team gets together and begins to identify all the aspects of the project. They tend to find out how to start developing the plan.
Development
Once the requirements are finalized, the work of development begins. A high-quality working project is delivered in several sprints.
Release
The release is when the product or project is deployed and is now being used by end-users. The stages are monitored for bugs and defects.
Retirement
The last stage of retirement states a newer release of the product after some minor software changes are made, or bugs are resolved.
Pros of Agile Model
- The Agile Model is best known for its adaptability, as it is well suited to deal with the changes in customer needs.
- The model allows inputs from clients or stakeholders with the project team, which helps in a better understanding of the client’s needs.
- The process of testing is done continuously and simultaneously in the Agile project. This helps in detecting and fixing bugs early, which improves the quality of deliverables.
- The entire process is transparent, which enables the stakeholders and the team to know what is exactly happening in the project.
- Since the focus of the model is on business value, the part of the project that is most important to the client could be delivered first.
Cons of Agile Model
- Agile Methodology is not beneficial for small development projects.
- The cost of implementation in the case of Agile projects is more as compared to other development methodologies.
- It requires a team well versed with all the Agile concepts, as the methodology involves a lot of commitment and discipline.
- The method lacks a proper structure in comparison to the Waterfall Model. So, the project becomes challenging at times, which requires a highly skilled team to be managed.
Waterfall vs. Agile: How To Choose the Right Methodology for Your Project
The comparison between the two methodologies will help you differentiate broadly between the two methods, and eventually help you in choosing the best methodology for your project.
Let us consider the differences between the Agile Model and the Waterfall Model, depending on various factors.
| Agile | Waterfall |
| Life Cycle | The Agile Model is a continuous iteration life cycle model for developing and testing software | The Waterfall Model is a linear sequential model for developing and testing software |
| Rigidity | Agile Methodology is a flexible way of building software | Waterfall Methodology is a rigid, structured way of software development |
| Collaboration | Agile Model is a highly collaborative approach towards software development, yielding a better output | Waterfall Model is the least flexible and follows a sequence of steps, not allowing the team to collaborate |
| Process | The entire process of development is divided into sprints | The software development process is broken down into several phases |
| Changes | In the Agile approach, the changes may be made even after the initial planning is completed | In the Waterfall approach, the development requirements cannot be changed once the project development begins |
| Software Development | With reference to the Agile Model, the process of software development is a collection of many different projects | With reference to the Waterfall Model, software development is completed as a single project or deliverable |
| Testing | In the Agile Model, testing is performed in the same iteration as programming or building | In the Waterfall Model, the testing phase comes after the build phase |
| Focus | The Agile Model strictly focuses on making an easy approach for team interaction and customer satisfaction | The Waterfall Model focuses on the progression of steps. It has two important elements: products and processes |
| Projects | The process is well suited for projects where requirements are expected to change and evolve | Best suited for projects that have well-defined requirements and changes are not expected |
| Customer Satisfaction | The Agile process focuses on customer satisfaction, hence involving them throughout the development phase | The Waterfall approach is more of an internal process, hence not requiring the participation of customers |
Why Does Agile Reject Waterfall?
The rigid structure of Waterfall did not permit any changes in the late stage of the software, and this created problems as developers can make several significant improvements at any stage. So several groups worldwide started experimenting with various software models, including scrum, extreme programming, pragmatic programming, and crystal. And finally, in 2001, the representatives of these models signed an 'Agile Manifesto' containing 4 values and 12 principles. These principles ensured software development was fast and prioritized working software over comprehensive documentation.
How Do Waterfall and Agile Compare?
Waterfall and Agile prioritize different philosophies. For example, the waterfall model chooses rigidity and the ability to conform to initial requirements, and the agile model prioritizes flexibility and fast delivery.
In a waterfall model, developers have limited interactions with stakeholders, while the agile model encourages continuous interaction with clients. That means the changes to the requirements of the finished product have a high probability.
When is Waterfall Better Than Agile?
The Waterfall model is better than Agile when you need:
- Rigidity over flexibility: Industries like banks, manufacturing, and defense need a rigid structure as the initial requirements often include security. These fields may benefit from the Waterfall methodology.
- Documentation over Working software: Waterfall models can be more helpful if your project requires comprehensive documentation. The rigid structure makes documents more efficient.
- Compartmentalization over Collaboration: Waterfall models encourage isolation between departments and stakeholders. So if you don't need to collaborate with your clients, Waterfall is more beneficial.
Advantages of Agile Over Waterfall
Advantages of Agile vs. Waterfall:
- Agile offers flexibility to make changes to the software even during the late stages of the SDLC.
- You can do more collaboration with the clients, ensuring more customer satisfaction.
- Developers can ensure continuous delivery of working software instead of being stuck in a phase.
Can You Combine Agile and Waterfall?
Yes, you can combine Agile and Waterfall SDLC methodology by using one model for a particular set of phases and the other for the rest of the development phases.
As mentioned in the above section, both Agile and Waterfall models have pros and cons; therefore, companies use a combination of these methods for various phases. The decision to use which methodology for development phases depends on whether you want the SDLC phase to have collaboration or rigidity. For example, banking
the sector often uses waterfall models for requirements and design stages but Agile models for the development stage.
In conclusion, Agile and Waterfall models are popular project management models in software development. Agile prioritizes collaboration, while Waterfall chooses a rigid structure; however, successful software development often employs both methodologies.
Conclusion
By now you would have been well versed with the basics of both the Waterfall Model and the Agile Model. We saw several factors that could be a deciding factor in Agile Vs. Waterfall Methodology section. The differences will help you choose the model that would be a better fit for your project. Depending on the size of the project, the time duration you have, or your team’s expertise you may choose the ideal methodology for your project. This will help you build the project efficiently and effectively.
So, if you are planning to become a Scrum Master, this is the right time to invest in the Certified ScrumMaster certification course.
Do you have any questions for us? Do let us know in the comment section of the Agile Vs. Waterfall Methodology article. We shall have our experts answer it for you.
