When an organization starts with a new software project then the team has to deal with one of the main questions is Agile Vs Waterfall? Because each software project follows a different model of development where the team should be set up, how to approach and what are the alternatives for software development.
What Is Waterfall Model?
If you have a development team that is not very experienced then it is best to use the Waterfall Model, as this will provide more control and a clear picture of what needs to be done and how. There will normally be a better quality of the application that is delivered, but this can take longer than some other models and there can be time lags between the various stages of development.
The Waterfall Model always has a defined start and endpoint, along with a series of checkpoints along the way. The model involves a single phase at a time, from requirements through to testing and implementation. If something goes wrong at any point in the process from design to development, then it could result in a lot of rework being done.
What is Waterfall methodology?
The waterfall model is also known as the conventional or “big-bang” approach. Waterfall methodology has been the dominant project delivery system for many decades and the name comes from the analogy with a waterfall, which flows from top to bottom in an unbroken sequence of stages. Each stage must be completed before subsequent stages can begin.
Waterfall methodology is sequential in nature and focuses on one set of tasks at a time. It moves forward in straight lines, with little overlap or integration of stages until the final product has been completed. The Waterfall model does not accept feedback; it just keeps moving forward towards completion.
The Waterfall approach provides a simple, straightforward plan for all the work. The waterfall model is very structured and disciplined, which often makes it easier to produce a project plan than with other models.
Although the Waterfall methodology provides consistency and predictability in delivering software solutions, its weakness lies in its inability to accommodate feedback or changes in requirements during development that may become apparent as testing progresses.
Another weakness is the implication of a rather lengthy and inflexible project cycle. Another major weakness of the Waterfall model is that it requires a large team with lots of overhead costs in order to manage all the tasks.
The waterfall approach doesn’t match well with rapidly changing requirements or unpredictable requirements, since it demands a complete definition prior to development activities.
Advantages of Waterfall Model
- The project is planned in detail, with all the tasks identified and resources allocated.
- There are no ‘surprises’ because of the very structured nature of this model.
- Quality can be guaranteed by following a strict development process for every stage, including testing and documentation of each stage before proceeding to the next one.
- The waterfall methodology suits organizations in which it is easy to define the requirements for a particular project. Also, if it is likely that there will be little or no change in requirements before the final system delivery.
- Teams are larger and thus have more expertise and experience. This makes it easier to get good quality output with a high level of predictability.
- The development team can be very secure in the knowledge that they have a well-defined plan to follow and, at each stage, there is the opportunity for thorough checking.
- Software can easily be produced within budget (as long as the resources are available).
- Waterfall model has the most precise and formal documentation process.
- Waterfall model is the best choice for a project that has strict requirements, because it provides maximum decision certainty early in the planning phase.
- Waterfall methodology doesn’t consider change during development, or factors like quality and then each stage must be completed before moving on to the next one.
- Waterfall model is suited best to situations where a system will not evolve, or change, significantly prior to implementation.
- The waterfall methodology is characterized by “the fixed order of sequence” which requires the project manager and team members to carry out all tasks in the specified order rather than performing some activities concurrently. This makes it vulnerable to schedule delays if unanticipated issues and problems arise.
Disadvantages of Waterfall Model
- This model is considered inflexible, since it cannot adapt to change or problems as they arise; changes mean starting the process over again from the beginning. Any changes are made at great expense with very little return on investment. These changes can be made quickly in more flexible models like Spiral or Agile model.
- A key feature of the waterfall model is that all work and documents must pass through each phase before proceeding to the next, which required duplication of effort within phases. This means that a lot of time may be wasted during the implementation of this methodology.
- Waterfall model is heavily reliant on the completion of one phase before moving on to the next, so if a particular project manager or team member leaves after completing part of their work, it can block progress in other phases until a qualified alternative is found.
- Since each stage has to be completed before proceeding to the next, this makes it difficult to estimate how long each phase will take.
- The higher cost associated with the delivery of the project, especially in terms of time and money may lead to a less competitive or inferior solution being offered or accepted than originally planned for.
- Waterfall model is not suitable for R&D, scientific or highly creative projects.
- It is not suitable for projects with a large number of stakeholders. The end result tends to be too generic and disconnected from the needs of individual customers or clients, since it aims to satisfy the requirements of all stakeholders equally.
- Waterfall model is unsuitable in situations where there are frequent changes in requirements, or when innovations are expected. Changes that occur after the completion of a particular phase have to be made at great expense as it requires work to start from scratch on tasks completed in earlier phases.
- This model tends to rely heavily on documentation and paperwork during each phase, so if there is a failure to produce these correctly or on time it can cause delays and the project may be unworkable.
- The presence of serious and critical flaws in this model make it vulnerable to cost overruns, schedule delays or even cancellation.
- Work is carried out in phases but the work done within each phase is not always checked for quality, so this requires a lot of time and effort during the implementation stage.
- If any one phase takes longer than expected or is abandoned during the implementation, then this can have a knock on affect on other stages and will ultimately cause delays in delivery of the project.
- It should not be used if there are critical dependencies between tasks because these cannot be identified before work starts on each phase, and there is no flexibility to deal with them.
- The model is not flexible enough to allow changes that occur during the implementation of a particular phase, so if something goes wrong in one phase then an attempt must be made to go back and re-do part or all of this phase before proceeding to the next.
- If a decision is made mid-way through a particular phase that requires other parts of the project to be altered, then this will delay the implementation process.
- Project managers need to have good leadership capabilities and must be able to handle continuous change over numerous stages in order to deliver successful projects.
- The output from each phase has already had some thought and planning put into it, so there can be an increased workload during implementation if adjustments have to be made at the request of stakeholders. This could result in a reduction in quality or increase time on site for implementation.
- The model assumes that resources are unlimited and that anyone who is interested in contributing will work free of charge, and that a project will be completed on time and within budget.
- It assumes that the project can be broken down into manageable units of work, therefore there is a risk of overlooking issues during planning or implementation that may affect the success of the whole project if someone notices them later.
- The model works best when all stakeholders are able to agree on the needs of the project, as well as being able to plan for its implementation. This makes it unsuitable for projects that are very controversial or can be seen to have one particular stakeholder or group of stakeholders benefiting at the expense of another.
- Resource selection is based on detailed planning which means that if this part of the project is not thought out carefully, then there is a possibility that the wrong resources will be assigned to different tasks.
- The model uses many documents and complex summaries in order to plan for implementation, this can mean that updates or amendments are held up because they have to be sent back and forth between stakeholders and project managers via these lengthy reports.
- This model is not suitable for use in projects where strict deadlines need to be met, as the project is broken up into many stages and this can add to complexity and make it more difficult to achieve ambitious deadlines.
- The work done at each phase often needs to be signed off by a client or stakeholder before the next
What Is Agile Development?
A team taking this model should ideally have a lot of experience, and it will normally be more suitable for an organization with fixed resources. However, this might not be the best option for an organization that will have to deal with changes along the way and wants a quicker turnaround time. That would be more suitable to use a model that is more flexible and agile in nature.
What is the Agile methodology?
Agile project management is a modern, lightweight approach to software development. We use this term “light-weight” because Agile projects generally do not require all the paperwork and cost that traditional (sometimes referred to as “heavy-weight”) approaches require. This does not mean that Agile projects are less professional or don’t deliver quality. In fact, Agile projects usually deliver higher quality software earlier than traditional approaches because they are so focused on the customer’s needs.
However, as Agile projects are not viewed as “heavy-weight”, many companies do not consider them a serious and viable alternative to traditional approaches.
The cornerstone of Agile software development is short iterative cycles that enable us to continually deliver working software to our customers. We call these iterations or sprints because they last about two weeks each (although they can be shorter or longer depending on the project and our customers’ needs). In these short iterations, we are able to deliver working, tested features every two weeks. By delivering working software so frequently, Agile projects eliminate much of the rework and wasted time that traditional approaches are known for.
Agile projects have just a few key inputs and deliverables per sprint. The inputs to an Agile project are user stories and requirements documents (such as use cases, scenarios, and business rules). These will be discussed more in a later article. The key output of each Agile project is working software that can be tested by the customer.
The requirements documents for an Agile project consist of those documents that help us to plan for implementation, as well as those documents which we use to define our working software. These requirements are usually grouped into three categories: User Stories (see part 2 of this article)
This framework is a simple way of looking at how all the various pieces and players come together in an Agile project. It helps us keep project stakeholders and teams focused on the real goal of the project, which is to deliver working software.
Advantages of the Agile Model
- Much less paperwork and overhead than traditional approaches.
- Stakeholders and business users are more involved in the project because they can see working software being produced during each iteration. They also have a say in what features and functionality will be included in the next iteration/sprint.
- Unconventional responses, solutions or approaches to problems are welcomed by Agile teams.
- Agile teams are more autonomous, empowered and responsive than traditional approaches. This flexibility is crucial to delivering working software in two-week iterations.
- Working software is delivered early in the project, before significant time or money is spent on design, documentation and change management within an organization. Compared to traditional projects where 30% of budgets are spent in these areas, an Agile project will spend less than 10% of its budget on this.
- In most cases, Agile projects are easier to manage because they have fewer dependencies (no detailed design documents) and oversight (thanks to working software produced at each iteration).
Disadvantages of the Agile Model
- Projects can be more difficult to plan than traditional approaches due in part to the lack of a complete requirements specification.
- There is no room for error and it is critical that the Agile team have its act together before each iteration begins. Teams must focus on quality, documentation (including user stories) and testing.
- Agile teams need to be much more disciplined than traditional approaches. Each member of the team must be on the same page and focused on delivering working software in each iteration (as well as having a structured approach that will help them deliver this).
- Agile teams report directly to the customer because by doing so they are able to respond quickly to changes and produce new features earlier than traditional approaches. But they also need to be able to work without oversight and, from time-to-time, release their working software directly into production (i.e., without it being tested by the customer) .
- Agile approaches are more risky than traditional projects because there is no room for error in each iteration. In a traditional approach, if something goes horribly wrong in a project to the point where testing isn’t possible, we can always “go back to the drawing board” and fix both the design and document it before moving forward. Agile projects that suffer from this problem usually fail completely.
- Working software is the primary focus of an agile project because it has several advantages over documentation. Whereas documentation is out-of-date by the time it is produced, working software can be used as a demonstration of progress in each iteration. And working software can easily be updated or modified after being implemented if the customer asks for changes.
- This framework is very simple and well suited to small projects with non-technical customers that are looking to get something out the door quickly. It is also useful for larger projects in which a release has been delayed because the requirements are still being debated, designed or specced by business analysts or vendors. What agile methodology could you use to deliver working software to your project stakeholders?
Agile vs Waterfall Comparison:
Waterfall Methodology: This is a linear approach and it has the advantage that there is more control over the process and a better quality product is produced. This model is more suitable for the client and they are able to see how the project will pan out along with a clear start and endpoint.
Agile Methodology: This is a more flexible approach and it has the advantage that it can respond to change, so if something changes the project can be adjusted accordingly. This might not be the best option for a client who wants to see clear and strict milestones throughout the development process as each phase will not necessarily have a defining start and endpoint.
So, which of the two models is best suitable for your project? This depends on a number of factors and will determine what is the best solution for your project.
Agile vs Waterfall: Advantages/Disadvantages
Waterfall Methodology Advantages:
- More control over the process.
- A better quality product.
- The client is able to see a clear start and end point.
- This model is relatively easier to plan and schedule this is because each phase has a fixed start and end point.
- There will be fewer rework, so less time and money is wasted by the team due to errors in the development process.
- There is a clear scope of work.
Waterfall Methodology Disadvantages:
- It can take time for the team to successfully complete each phase.
- It can result in too much control, so the team could potentially miss out on new opportunities because of a fixed schedule.
- There may be too much focus on the end goal, so there will be a lack of communication and interaction throughout each step in particular between designers and developers.
- It is hard for the client to see issues that might arise, and it can lead to stress and lack of communication between parties.
Agile Methodology Advantages:
- It is flexible and can respond to change.
- There will be fewer difficulties that arise along the way.
- The client will be kept input.
- There is more communication and collaboration along the way between designers and developers.
- It can help a team to improve their productivity and the quality of the final product.
Agile Methodology Disadvantages:
- The client does not know exactly how long a project will take.
- It is difficult to know exactly how much money will be spent on a project.
- There may not be enough control over the project to ensure it is moved forward.
Difference Between Agile vs Waterfall Methodology
|The Waterfall development process is divided into distinct stages.||Agile breaks the project development lifecycle into sprints.|
|Software development is completed as one single project.||Agile can be considered as a set of many different projects.|
|The method is a sequential design process.||The methodology follows an incremental approach.|
|This is a structured software development approach so most times it can be quite rigid.||Flexibility is what makes Agile different.|
|There is no scope for changing the requirements once the project development starts.||The approach is quite flexible that allows changes in the project development requirements even if the initial planning has been completed.|
|Waterfall demonstrates a project mindset and places its focus completely on the project accomplishment.||Agile is a mindset where the software product satisfies the needs of the end clients and changes itself as per the client’s demands.|
|All the project development phases are completed once.||The method follows an iterative approach. Different phases may appear more than once.|
|The testing plan is rarely discussed during the test phase.||The testing plan is reviewed after each sprint.|
|This approach looks ideal for projects that have definite requirements and changes not at all expected.||According to Agile, the requirements are expected to change and evolve.|
|The testing phase comes after the build phase.||In Agile, testing is performed concurrently with software development.|
|Due to the getting risk agreement at the beginning of the process, Waterfall reduces risks in the firm-fixed-price contracts.||Agile works exceptionally well with time and materials or non-fixed funding.|
|A detailed description needs to implement Waterfall.||You may change the description of project details anytime during the SDLC process.|
|The process is always straightforward so, the project manager plays an essential role during every SDLC stage.||Agile team members are interchangeable, so they work faster. There is no need for project managers as the projects are managed by the entire team.|
|Team coordination/synchronization looks rather limited.||The method implies small but dedicated teams with a high degree of coordination and synchronization.|
|Business analysis prepares requirements before the project begins.||A product owner with a team prepares requirements every day during a project.|
In this article, we have shared with you the difference between Agile vs Waterfall Comparison. Here we have discussed Waterfall Methodology and Agile Methodology. We also mentioned the advantages, disadvantages of both methodologies.
In this article, we have discussed what is Agile vs Waterfall Methodology. We also listed the difference between practical differences. Hope you enjoy this article.
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