Scrum and Waterfall are the two different models used for software development. New startup companies are trending towards agile methodologies whereas, the old software firm which were using other software development methodologies are shifting towards agile to co-op with the world needs.
Scrum is part of agile methodologies which is adopted by many IT industries as to meet the global needs in a high pace. Considering scrum and waterfall methodologies, IT industries are moving with scrum rather than waterfall methodologies because of various advantages over it. Let us see the various difference between scrum and waterfall methodologies,
Waterfall model has different stage through which whole project is developed and those are requirement gathering, requirement analysis, designing, implementation, deployment and testing. The next phase of project development is initiated only when previous stage of development is completed. Once all the stages are completed then the software is tested and deployed. The below diagram shows the process of waterfall methodology,
Whereas, in scrum, a team involves 6 to 8 members throughout the whole software development. In scrum software project is divided into small parts called ’sprints’. The team work as per the sprints. The duration for each sprint is about 1-4 weeks. Sprint has various stages those are product backlog that is nothing but the product features, while next stage is sprint backlog(stories). Later once stories are finalized sprint planning is done. Everyday daily stand-up meeting is done and all team member must be involved along with scrum master. Later at the end of sprint the sprint review meeting is conducted in which all issues and work done are discussed. While in sprint retrospective meeting, the team discuss about how they did with scrum, how well they are performing and what changes must be adopted to achieve the goal more pace and convenience. The diagram show the flow of scrum methodology,
- Change Flexibility:
Waterfall model is rigid as any changes are not effective once the project development is initiated. So, client must be specific about his requirement and any unexpected changes other than documented will not be reflected into the project once the development starts.
In scrum, any unexpected changes are always welcomed as those changes are analyzed and taken into consideration to satisfy the client needs. Hence scrum methodology possesses change flexibility.
- Documentation Need:
Waterfall Model rely on documentation. As during the start and end of every stages the documentation is done and as per that next stage is initiated. Hence without documentation waterfall model won’t exist.
Whereas in scrum, documentation is not necessary to initiate the project. Only technical documents are prepared by the developer for every sprint.
In waterfall methodology, the project is delivered only when all stages of development are completed.
While in scrum software is delivered on regular basis. Hence this keep track of project development, and client satisfaction.
Project must be delivered as per the deadlines specified during the project initiation. Hence in waterfall methodology the project development is planned as per the deadlines and budget.
In scrum the deadlines does not play an important role. As it is not necessary to commit fixed date for project deliverable. But because of this some project make exceed development time which can be a result of poor performance of team or scrum master.
Waterfall Model make use of ‘Gantt’ chart which is used to schedule the start and end date for the project along with the development stages.
While scrum use ‘burndown’ chart which is used to identify number of sprints need to be performed for completing the project.
- Software Development Life-cycle Nature:
Waterfall model is also known as ‘Sequential Model’ as it follows all the stages one after another. Unless and until previous stage is completed next stage cannot be initiated. Hence this restrict any unexpected changes into the project and strictly follow as per the requirement documented during the early stage of development.
In scrum the life-cycle of development is iterative, hence any unexpected changes from the product owner can be accommodate during the development of project. Hence in all sprints changes are verified and are implemented.
- Experienced Team Members:
Team of 6-8 member form the scrum team including scrum master. It is mandatory to have experienced person as a team member as scrum in known for it fast project development which is not possible with the person without any experience.
Whereas in waterfall model it is not necessary to have an experience candidate as it has various department and various teams are involved in project development.
Meetings are conducted during start and end of every stage of development in waterfall methodology. While in scrum, daily stand-up meetings are conducted to track the project work.
- Advantages of Scrum Over Waterfall Methodology:
Scrum methodology is adopted for large project to develop at faster rate rather than following all stages of development which waterfall model does. Waterfall Model is good for small project. Project deliverable are done at regular basis in scrum. While in waterfall methodology, project is delivered only when all stages of development are completed. Changes can be accommodated during the phase of development in scrum while in waterfall methodology, it restricts to adopt any uncertain requirement or changes from client and they stick to those requirements which were documented during early phase of development.
- Advantages of Waterfall Over Scrum Methodology:
Waterfall methodology possess fixed deadlines and deliverable dates. while in scrum, it can face risk of scope creep as there is no fixed project deliverable date and no deadlines as project is delivered on regular basis in the form of sprints hence stakeholders can go on adding or changing functionalities which certainly increase project span of development and budget too.
University of Central Missouri