Difference Between Waterfall and Agile Model
Posted: Mar 07, 2020
All You Need to Know About Waterfall Methodologies Vs Agile: To Know what is the exact difference between the Waterfall and Agile methodology of Software Development and which is the best suitable model for your project with the pros and cons of each.
Initially, it is very important for us to know the basic meaning of the terms Waterfall and Agile, before exploring the differences between them.
In a simple way, we describe, Agile means ‘able to move quickly and easily’ and hence that is what it means when it comes to the Agile development methodology.IntroductionThe waterfall model is a linear sequential model in which the progress flows majorly in one direction downwards through the phases of requirement gathering, analysis, design, development, testing, deployment, and maintenance.
The finished product is delivered once to the customer at the end of the deployment phase. This is the oldest model for software development.
Agile is a method of project management that is represented by splitting of tasks into shorter segments of work with frequent reviews and adaptation of plans.
This same example applies to the concept of project management when it comes to the waterfall model. This is a method of project management, that is represented by serial stages and a fixed plan of work.
In the Agile approach, the software development, the whole project is broken down into small manageable Segments or units. Agile is based on the iterative development model where the requirements and the solutions grow through a collective effort of self-disciplined & the cross-functional teams and their customers/stakeholders. There are multiple iterations (often called Sprints) of adaptive planning, design, development, testing (these phases also overlap with each other in the sprint) and delivery. At the end of each sprint, an MVP (Minimum Viable Product) is delivered. MVP (Minimum Viable Product) is agreed to a subset of the product features. In this table, we will give you brief information between these two methodologies and the differences between them.Agile Vs. Waterfall Comparison Table
WaterfallAgileWaterfall methodology is a model, where each stage of the product’s life cycle occurs in a sequence. The progress of the project flows gradually downwards, which resembles a waterfall.Agile methodology is a model that follows a linear, sequential, and iterative approach.This model believes in a one-time massive whole delivery.This model believes in multiple small chunks (unit) of delivery at defined time intervals.The product is delivered at the end of the SDLC.An MVP (Minimum Viable Product) is delivered at the end of each sprint.Its a traditional and old-fashioned approach.It’s a new and modern approach.One single cycle and single release.The repetitive number of iterations and multiple releases.It divides the software development lifecycle into different phases.It divides the software development lifecycle (SDLC) into sprints.This project has gotten so big, I’m not sure I’ll be able to deliver it!It’s so much better delivering this project in bite-size sectionsThe process is treated as one, a single project which is further divided into different phases.The process is divided into multiple projects and each project has it’s own iteration of different stages.Structured and rigid model.This methodology is known for its flexibility.Long-term planning scale.Short term planning scale.A long-distance exists between the customer and the developer.A short distance exists between the developer and the customer.Long time between specification and implementation.The short time between specification and implementation.Takes a long time to discover problems.Problems are discovered quickly.High project schedule risk.Low project schedule risk.Less ability to respond quickly to change.High ability to respond quickly to change.The testing phase occurs only after the completion of the development phase.Testing is generally performed in parallel with the development to ensure quality continuously.The customer is involved only at the requirement gathering phase and after, there is no involvement of the customer.
It’s coming into the picture only, at the time of delivery of the product.The customer is involved throughout the project and feedback is taken from the customer from time to time to ensure customer satisfactionSuitable for those projects which have clearly defined their requirements and those which are not expecting changes.Suitable for the projects which have to evolve and those which involve changing the requirements.Stringently sequential process.A highly collaborative software development process leads to better team efforts and quick problem-solving.Exhibits a project mindset.Introduces a product mindset and thus it is more customer-focused.Formal and hierarchical. The project manager is the decision-maker.It is Informal. The entire team is responsible for decision making.This model anticipates that there will be no changes throughout the project.This model is based on adaptation and it embraces changes.What is the Difference Between Waterfall and Agile Methodology
Let’s know more about the pros and cons of agile and waterfall models in detail:Waterfall ModelThere are various Pros and Cons of the Waterfall Model are as follows :
- Forward & backward planning and implementation is easy.
- The waterfall model is simple to use and easy to understand. It does not require any special training for project managers or employees. It has an easy learning curve.
- Being rigid in the nature, it is easy to manage the waterfall cycle. Each phase has a review process and fixed deliverables.
- Less complexity as the phases does not overlap. Phases are followed one after another. It uses a clear structure when compared to other software development methodologies. The project goes through fixed sequential steps, starting from the requirement gathering and finally lands at maintenance.
- Due to phased development, discipline is enforced, and timescales can be kept easily.
- Works well for small projects where we have fixed and crystal-clear requirements.
- Processes and results are well-documented.
- Arranging tasks is easy.
- It is easy to measure the progress as the start and endpoints of each phase are predetermined.
- There are almost no changes in the requirements throughout the project, hence the tasks remain stable for the developers. Also, it is very easy for any new developer to quickly learn and start the work.
- There are no financial surprises. Once the requirements are fixed or gather, then the final cost can be calculated before starting the development.
- Caters for a sequential funding model.
- Its detailed design makes the final expected outcome very clear to everyone.
- The functional requirement specification documented in the requirement gathering phase gives enough details to the testers to design the test scenarios and the test cases. Therefore, the testing process becomes easy in the waterfall model.
- As all the requirements must be clearly and known before starting the development, it’s delays the project.
- Requires extensive research as per the user needs.
- At the initial phase of the project, it is challenging for the customer is clearly define and conceptualize their requirements in the form of functional specifications. Hence, there is a high possibility for them, to change their minds after seeing the end product. This change can also occur due to a market influence or business plan. Low flexibility in this model makes it very difficult to accommodate any such changes, especially when the product needs to be re-engineered to a large extent.
- No working model is produced until the later stage during the waterfall lifecycle.
- Slow delivery times. The customer is not able to see the product until it is fully completed.
- The customer has no opportunity to get familiar with the system in advance. The waterfall model is more of an internal process and keeps the end-user excluded.
- The client is not informed well about the health of the project.
- Deadlines can be missed if strict management and regular monitoring are not kept.
- There is no room for changes even it is visible during the development as the product is not going to cater to the market requirement.
- Delays testing until after completion. Also, large revisions is very very costly at this point.
- High risk and uncertainty are involved in the waterfall model as there is too much room for issues to remain unnoticed until the project comes near to completion.
- Not a suitable model for long, complex and ongoing projects.
- It is difficult to measure the progress within each phase.
- One of the biggest advantages of the agile model is its great adaptability. Adaptability means ‘responding to change’. Agile is very flexible in dealing with the changes in the customer priorities and needs.
- Allows to constantly re-prioritize and refine the overall product backlog without affecting the current iteration in which the team is focused on delivering the (Minimum Viable Product) MVP. The changes can be planned for the next iteration, therefore offering an opportunity to bring in the changes within a few weeks only.
- Agile methodology offers a great degree of stakeholder engagement. The project and the client team meet before, during and after each sprint. As the customer is constantly involved throughout the project or a final result, there are more opportunities for the team to clearly understand the customer’s vision.
- The working software is delivered early and frequently. This increases the stakeholder’s trust in the team and encourages the team to stay highly committed to the project.
- This model gives transparency. Both the team and the stakeholders know well about what is happening. The client can see the progress of the work.
- Fixed schedule sprints of one to four weeks allow for early and predictable delivery. New features are released frequently and quickly in a time-boxed manner.
- Agile is customer-centric. It does not just deliver the functionality but also focuses on delivering the feature that is of some value to the user. Each user story has business-focused acceptance criteria.
- Valuable customer feedback is gained early in the project and the changes to the product can be made as required.
- The focus is on business value. It first delivers what is most important to the client.
- Improves the quality of deliverables. Unlike waterfall, testing is continuously and frequently done in an agile project and that, in turn, helps in detecting and fixing the issues early.
- Agile supports TDD (Test Driven Development) approach which provides enough time to create unit tests for the features that are going to be released through MVP.
- Also, by producing frequent builds, any misalignment with the customer requirements also be detected and fixed early.
- As we get immediate user feedback after each MVP release, the risk of project failure is low, when you are working in an Agile way.
- Agile promotes teamwork. There is a great interaction, collaboration, harmony, and enthusiasm among the Agile team members.
- The schedule and cost estimates of each sprint are communicated to the client prior to the start of the sprint. This improves decision making as the user can understand the cost of each feature and prioritize accordingly.
- In an agile project, there is room for continuous improvement. Lessons learned from the past sprints can be applied in the next (upcoming) sprints.
- It is often seen that Agile teams have a tendency to neglect documentation. This is because the Agile manifesto more focuses on working software than the comprehensive documentation. However, the teams should maintain the right balance between the documentation and code.
- As it requires a high degree of customer involvement, it can sometimes be problematic for customers who do not have much time and interest to participate in the project.
- It does not work well if the team is lacking commitment and dedication. Waterfall requires involvement, where Agile requires commitment.
- If the initial architecture and design are weak, then frequent refactoring is required.
- When we compared to the waterfall, Agile is difficult to practice. The team members must be well versed in Agile concepts. It requires a lot of discipline in doing the work and commitment to practice Agile.
- Due to re-prioritization, it is less predictable than what will be delivered at the end of the sprint.
- Due to time-boxed delivery and frequent re-prioritization, there are chances for a few features to not get delivered in the allocated timeline. This leads to additional sprints and additional costs. This can also make a problem to the nebulous timelines.
- Lack of structure when compared to the waterfall, it demands self-discipline, highly proficient and cross-skilled teams. Without this, the project can really be a difficult and challenging one.
- Availability is less of a blueprint of the final deliverable.
- Sometimes the external stakeholder cannot resist following the Agile approach. In such cases, the education and the training about Agile are required to a wide audience.
Let us now explore the differences between waterfall and agile testing.
From the perspective of software testing, it is important for us to have a fair idea about how Waterfall testing is different from agile testing.Differences Between Waterfall and Agile Testing Methodology
Waterfall TestingAgile TestingWaterfall Testing begins after when the completion of the development and builds phases.Agile Testing starts concurrently with the development phase.Planning is done just for a once before the testing phase.Planning is done before the project starts and is often done during the project.The test plan is rarely reviewed during the project.The test plan is reviewed after every sprint.It is quite challenging for the testing team to propose any changes to the requirements.The test team actively participates in the change process and requirement gathering.Test cases are created once for all the functionalities.Test cases are created sprint by sprint for the functionalities that need to be released in each and every sprint.Acceptance testing is performed once by the client after the release.Acceptance, testing can be done after each iteration and before the delivery by a business analyst (BAs) or the test team.
Later, it is done by the customer after each release.Development teams and the Test teams are separated by a clear boundary and there is a strict and formal communication between them.The test team and the development teams are integrated as one team and there is a free flow of communication between them.Verbose and extensive test documentation.Test documentation is done only as much as necessary.Test estimates and assignments are often the responsibility of the test manager.Test estimates and assignments are the shared responsibility of the test engineers and the team who are involved in providing the estimates and choosing their tasks.Regression testing is rarely done, and it involves the execution of all the test cases.Regression testing is done after each iteration and it’s involves only those test cases that are required.ConclusionIn this article, we learned the exact differences between the modern Agile approach and the traditional waterfall method of software development and testing with a comparison table covering the pros and cons of each model. So MCAL Global provides you the best training to you, MCAL has Master Business Analysis Training Programming
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