Agile vs Waterfall – How to Choose between them?

Project management methodologies are the step-by-step directives that assist in developing effective software projects. With so many diverse and overlapping approaches to handle the complexities of a project, the most difficult part is to decide which methodology will be effective for you.

Some of the key project management methodologies are Waterfall, Agile, Six Sigma, Scrum, Critical Path Method (CPM) and Critical Chain Project Management (CCPM). Waterfall and Agile are two diverse and popular methodologies for application development.

Waterfall Model – the linear sequential life cycle model

Waterfall is used as a linear sequential model in software development. It’s development process flows with static phases like conception, requirement analysis, design, implementation, system testing, deployment and maintenance. Waterfall model offers complete control on each and every phase of the project. However, it tends to be extremely stubborn when the changes in the project are anticipated. As in the waterfall model, every phase needs to be completed before the subsequent phase can commence. Also there is no scope of overlapping in the defined phases.

Requirement gathering and analysis is the foremost phase in this model. In this phase all the probable software requirements are gathered followed by design phase which helps in specifying system and hardware requirements. It assists in defining the complete system architecture.

Subsequent to design, the system is developed in small programs known as units. These units are integrated, developed and functionally tested which is referred to as Unit Testing. Post integration, the complete system is tested for any faults and failures.

User acceptance testing (UAT), also called Beta or End-User Testing is the final phase of the testing process. Throughout UAT, users test the software making sure it can manage the required job as per the specifications. Once the testing is done and there are no bugs or flaws, the project is then deployed to client environment.

If there are issues reported in the client environment, they are further solved in the maintenance phase. For fixing these problems patches are generated. For system performance improvements advanced versions are also released.

All the phases are cascaded to each other and perceived as flowing progressively downwards like a waterfall.

The Agile Way

Agile follows an iterative approach to application lifecycle management. As a substitute of handling all the planning upfront, it concentrates on being lean and creating minimum viable products (MVPs) by setting-up time periods. It brings improvements with every iteration.

The multiple phases of project development cycle can be executed in parallel, and a backlog is reserved for tracking chosen features and requirements. Agile methodologies give priority to teamwork, continuous user feedbacks, constant improvements and flexibility to adapt with varying requirements.

Agile vs. Waterfall – the never ending argument

You must probably be familiar with the never ending discussion this subject can bring up. As we discussed, on one side you have the conventional Waterfall methodology where development is managed as a linear series of phases starting from conception to final creation on the other side you have a supple, iterative and advanced development approach. So what makes these two approaches diverse? And what are the pros and cons??

PROS OF WATERFALL DEVELOPMENT

• Estimate clear deadlines: Waterfall’s foreseeable workflow methodology makes it simple to evaluate costs and estimate timelines.
• Well-organized process: As every development phase is clear with a start point and a fixed evaluation process, the project team completes all the defined tasks to proceed the whole project.
• Well documented: As each phase requires proper documentation, it is easy to use the logic of earlier projects and also create a strong base for future projects.
• Clear project updates: Foreseeable timelines and well-documented projects makes it simple to give status updates to all the project stakeholders including clients.

CONS OF WATERFALL DEVELOPMENT

• Modifications can be expensive: The major shortcoming is Waterfall’s inflexibility to manage change. Testing is executed late in the project life cycle, and if you discover that end users do not like the product you are developing, then it can be too late to retain improvements.
• Sluggish delivery times: It needs four phases of development to be accomplished before any coding commences, which means stakeholders and clients can’t view a working product until late in the project life cycle.
• Assembling requirements too early can be dicey: Clients and stakeholders often don’t know what they actually want until they’ve had an option to play with a working product model. But as the Waterfall model manages all the project requirement gathering early in the project life cycle, there’s always a tangible risk down the project line.
• Testing can be risky: Keeping all the testing activities in the end can be risky. It can lead to a terrible project launch if not managed well.

PROS OF AGILE DEVELOPMENT

• Flexibility: The principal benefit Agile development offers to businesses is its flexibility to change. Clients get faster solutions to their problems based on its priority. Stakeholders can line up required deliverables in a progressive way.
• Predict cost and time: As every sprint is of a fixed time duration, the project cost and time is easy to predict and relating to the status of work completed.
• Emphases on business value: With client regulating the priority of features, the development team understands what’s key to the client’s business and can deliver the features accordingly.
• Focus on user value and quality work: Focusing on features helps you fulfill the needs of actual users. Each feature delivers value and is not just a software element. Also, by dividing the project into manageable units, it gives you quality development, testing and collaboration.

CONS OF AGILE DEVELOPMENT

• Difficulty in defining project scope: There are difficulties faced in defining the project scope as there is much less predictability at the initial stages. This makes it tough to define projects commercially, especially when handling fixed price projects.
• Testing is needed throughout the project: Testers are required throughout the project lifecycle and this impacts the resource cost drastically.
• Lastly, common feedback is that agile development is relatively rigorous for technical teams. The need to develop every feature within each iteration and the intensity of maintaining multiple iterations is exhaustive and reduces the speed of your project.

Hybrid Model

The collaborative hybrid model combines both the models. Combination of Waterfall and Agile methodology safeguards the success of the project. It eliminates the weaknesses of both the models; and implements their advantages.

Conclusion

Both waterfall and Agile methodologies have their own merits and demerits. The important thing is to decide which one is suitable for your project. If your requirements seem to alter quickly, select Agile. If you know exactly what you require, waterfall should be a better option then. Or by going for a Hybrid model, you can combine the advantages of both methodologies for your project.

Do you favor the Agile or waterfall methodology? Why? Have you ever combined the two? What was the outcome? Let us know in the comments section.

This article was originally published on www.cygnet-infotech.com

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