Scrum and Waterfall are two of the most popular project management methodologies, and each has its own set of pros and cons. I have used both methodologies extensively throughout my 15 years in software development. So, you might be wondering which is the best fit for your project. Let’s discuss the main differences.
Scrum vs Waterfall: Key Differences
Scrum is an agile framework designed for iterative development. It prioritizes flexibility, collaboration, and delivering working products quickly. Waterfall is a traditional, linear and sequential project management methodology that executes projects in a predetermined order from start to finish.
The main differences between Scrum and Waterfall include:
- Flexibility: Scrum is adaptable; Waterfall is rigid.
- Deliverables: Scrum produces incremental products; Waterfall produces deliverables at the end.
- Planning: Scrum plans the entire project in smaller sprints; Waterfall plans the entire project upfront.
- Customer involvement: Scrum involves the customer throughout the project; Waterfall involves the customer only at specific milestones throughout the project.
- Team structure: Scrum uses cross-functional teams; Waterfall uses specialized teams.
When comparing the project lifecycle:
| Aspect | Scrum | Waterfall |
|---|---|---|
| Phases | Iterative sprints | Sequential phases |
| Duration | Sprints of 2-4 weeks | Months or years |
| Deliverables | Working product increments | Finished product at project completion |
| Changes | Welcomes and integrates changes | Discourages and is expensive to make changes |
In my experience, Scrum’s flexibility allows you to pivot quickly if market needs change. Waterfall’s structured method works well when project requirements are stable.
Recent data shows 71% of organizations use Agile (Scrum) methodologies. 30% still use traditional Waterfall methodologies. 54% use hybrid methodologies combining the practices of both. This illustrates the broader trend away from rigid methodologies in the business world and toward methodologies that can adapt quickly.
Project Structure and Phases
Scrum works in small time boxes known as sprints. Each sprint is a time box of 2-4 weeks and the goal of each sprint is to produce a potentially shippable product increment. The team plans, designs, implements, tests, and reviews in each sprint. The sprint review is a crucial part of this process, allowing the team to demonstrate their work and gather feedback.
Waterfall works in a sequence of process steps. Common steps include requirements, design, implementation, testing, and maintenance, and each step must be completed before the next starts.
In Scrum, planning is continuous. The team plans each sprint based on the most important work for that sprint and what it has learned from previous sprints. Waterfall requires a lot of upfront planning. The entire project scope is determined before starting work.
Scrum is designed to handle change. If a new requirement comes in or a significant change is needed, it can be scheduled into the next sprint. Waterfall treats change as the exception. Changes often require a change request, and they can be very expensive to make.
In Scrum, you get a potentially shippable product at the end of each sprint, even if it’s not the final product. In waterfall, you get the final product at the end of the project, and the in-between deliverables are often design or documentation.
Team Dynamics and Roles
Scrum has three primary scrum roles:
Product Owner: Represents stakeholders, manages the product backlog
Scrum Master: Guides the Scrum process, removes impediments
Development Team: Cross-functional team responsible for delivering the product
Waterfall has the following roles:
Project Manager: Oversees the project, manages resources
Team Leads: Lead specialized teams (e.g., design, development, testing)
Specialists: Domain experts who complete assigned tasks
Scrum teams are typically small (5 to 9 members) and cross-functional with all the skills necessary to deliver the product. Waterfall teams can be larger and are often organized by function.
Communication is informal and frequent in Scrum. Daily stand-ups, sprint planning, and sprint retrospectives create a constant flow of communication. Communication in Waterfall is more formal with scheduled meetings and written status reports.
Scrum favors a more collaborative decision-making style within the team. While the Product Owner has the final say on decisions, Waterfall is more often a top-down decision-making process. Decisions must often be approved by multiple layers of management.
Project Management and Control
Scrum is based on empirical process control and emphasizes transparency, inspection, and adaptation. In Scrum, the team regularly inspects progress and adapts plans based on results.
Waterfall is based on a predictive planning assumption, assuming all variables can be known and planned for in advance. This can create problems when things don’t go as planned.
Risk management in Scrum is ongoing as the team identifies and manages risks in every sprint. Waterfall typically has a dedicated risk management phase during the project where risks are identified and mitigated.
In Scrum, the team builds quality into the product throughout the development process. Each sprint should produce a “potentially shippable” product increment. Waterfall often has a specific testing phase at the end of the project.
In Scrum, the team assesses progress with tools like burndown charts and sprint backlogs, providing real-time progress visibility. Waterfall projects often assess progress with Gantt charts and milestone tracking – tracking progress against the original plan.
Companies that switch to Agile methodologies like Scrum see impressive benefits:
- 58% more project transparency
- 47% more team communication
- 42% faster project completion
- 38% higher deliverable quality
These statistics demonstrate the potential impact of using a more agile project management methodology.
Stakeholder Involvement and Client Interaction
Scrum encourages continuous stakeholder involvement. The Product Owner represents stakeholder concerns in daily decisions. Stakeholders have the opportunity to review and provide feedback at the end of each sprint.
In the Waterfall approach, you might schedule client reviews at the end of specific phases, which can leave long gaps without their input. The downside of this is stakeholders may only be able to provide feedback at the end of the project. This mismatch may result in rework or deliverables not matching stakeholder expectations.
It’s easy to incorporate feedback in Scrum. You can apply new learnings in the next sprint. The Waterfall methodology is not conducive to incorporating feedback during the project. Change requests will often require a very formal process in Waterfall.
In Scrum, you manage change requests through the product backlog. You consider new requirements alongside requests already in your backlog. Waterfall treats change requests as something to avoid. You’ll likely have lengthy discussions as a team to outline the impacts and then ask your manager for approval.
Client satisfaction in Scrum is incremental. You’re often demoing a more complete, higher-quality version of the product to customers. Waterfall stakeholders may not see the project come together until the very end, which is riskier for stakeholders who may be disappointed for us.
Project Timelines and Deliverables
Scrum generates incremental product releases. Each sprint has a goal of producing a piece of functionality that is truly shippable. This strategy enables early value delivery and frequent feedback.
Waterfall produces major deliverables at the end of each phase. These deliverables are often internal, like a requirements document or design specification. The final product is delivered at the end of the project.
Time to market is drastically different. You can produce functional software in a matter of weeks with Scrum. Waterfall could take months or even years to release the first version.
In Scrum, you handle project delays within a sprint. The team can manage this by adjusting scope or extending the sprint. Waterfall projects often “start over” when there’s a delay in a phase, meaning all subsequent phases are pushed back. This can dramatically delay when you deliver the final product.
The final product mindset is also different. With Scrum, clients anticipate a series of small improvements. It feels okay for the final product to change over time with customer feedback. On a waterfall project, clients expect you to deliver the final polished product at the end of the project.
Cost and Resource Management
Budget planning in Scrum is agile. Resources are budgeted sprint-by-sprint as priorities change. In contrast, Waterfall requires you to budget all resources at the beginning of the project.
Scrum is agile in how resources are allocated. Team members select tasks based on the sprint goal and their individual capacity. In contrast, Waterfall plans resource allocation months ahead of time based on projected needs.
Cost management in Scrum is about maximizing value delivered within the sprint budget. Waterfall is all about staying within the initial project budget. Any variance is closely managed and may require a change request.
Scrum has a different ROI story, as you can deliver incremental ROI through incremental delivery. Waterfall doesn’t realize the ROI until the end of the project.
Long-term costs are different. Scrum’s flexibility reduces the risk of building something that nobody will use. Waterfall’s rigidity will lead to higher costs if you realize you need to make substantial changes late in the project.
Pros and Cons Analysis
Advantages of Scrum:
- Flexibility to change requirements
- Early and frequent delivery of software
- Stakeholder feedback and involvement throughout the project
- Improved team communication and collaboration
- Higher customer satisfaction with frequent demos
Disadvantages of Scrum:
- Requires skilled team members and strong leadership
- Difficult to estimate long-term timelines
- Can result in scope creep if not controlled
- Documentation often takes a backseat to software development
- Not applicable to all businesses or projects
Advantages of Waterfall:
- Structured with clear milestones
- Easier to estimate costs and timelines
- Good documentation at each stage
- Most applicable to stable projects
- Best for industries with regulatory challenges
Disadvantages of Waterfall:
- Not flexible once the project begins
- Late software delivery
- Limited client involvement until late in the project
- Difficult to handle unforeseen challenges
- Can build features that are no longer needed
Recent research shows huge performance delta:
- Agile projects: 64% achieve goal, 42% successful, 9% fail
- Waterfall projects: 49% achieve goal, 26% successful, 29% fail
These stats clearly demonstrate the potential performance benefits of agile methodologies for achieving your goals and avoiding a failed project.
Industry-specific Applications
Scrum is the most common methodology today in software development and IT. These industries are constantly evolving, and Scrum’s iterative nature is well-suited to their fast pace. I’ve personally seen Scrum work well in various software projects, from mobile apps to large enterprise systems.
Waterfall is still popular today in industries like construction and manufacturing with more established processes and regulatory constraints. Waterfall’s more linear structure is useful in these industries to ensure the necessary control and documentation.
Many companies are now using a hybrid methodology. They may borrow aspects of both Scrum and Waterfall, depending on the specific use case. For example, a company might use Scrum to develop software, but Waterfall to manufacture a piece of hardware.
Factors that determine the methodology chosen include:
Project complexity and uncertainty
Team size and distribution
Regulatory constraints
Customer involvement
Company culture
One of the latest trends is the broader adoption of agile methodologies in various industries. Even industries that have traditionally used Waterfall methodologies are now finding ways to incorporate agile principles to gain more flexibility and deliver solutions faster. As organizations grow, they often need to consider scaling scrum to maintain agility across larger projects and teams.
Implementation Challenges and Considerations
The most common hurdles to Scrum adoption are:
- Pushback from team members or stakeholders
- Lack of knowledge about Scrum principles and practices
- Struggling to divide work into sprint-sized increments
- Difficulty in estimating complexity of tasks
- Keeping the team engaged on longer initiatives
The most common Waterfall challenges are:
- Failing to document all requirements upfront
- Inflexible when requirements change
- Problems discovered late in the process
- Long feedback loops
- Feeling pressured to stick to the plan even when you learn something new
Organizational culture has a big impact on which methodology will be successful. Scrum is ideal for companies with a culture of collaboration, transparency, and a desire to continuously improve. Waterfall tends to work better in very hierarchical organizations with a very clear chain of command.
Scrum requires a different skill set than Waterfall. Scrum requires team members to wear many hats and have a variety of skills. Waterfall relies more on specialists who are really good at one thing.
Switching between Scrum and Waterfall is challenging because it requires a different mindset and set of skills. You can make the transition easier through gradual implementation, starting with a small pilot project, and continuous training. Understanding the scrum pillars of transparency, inspection, and adaptation is crucial for successful Scrum implementation.
Performance Metrics and Success Factors
Scrum KPIs are often related to the project deliverable, such as:
- Sprint velocity
- Burndown charts
- Story point closure
- Sprint goal success rate
- Product backlog KPIs
Waterfall success metrics are often related to the project plan, including:
- Adherence to the project plan
- Budget variance
- Milestone completion
- Defect density during testing
- Validation criteria meeting
Measuring team productivity and efficiency is different for each method. In Scrum, productivity and efficiency revolve around delivering value and achieving sprint goals. In Waterfall, the productivity and efficiency of the team is often measured against how well they hit their planned timelines and resource usage.
For assessing customer satisfaction, Scrum does this continually during the project. Waterfall often waits until the end of the project or major milestone to assess customer satisfaction.
The long-term impact on organizational performance is different. Scrum will get your product to market faster and make it more adaptable. Waterfall will make your project more predictable and leave behind more documentation.
Ultimately, the decision to use Scrum or Waterfall will depend on what you’re building, your organization, and industry requirements. Both have their place, and both are effective when used in the right situation.
Let’s Close This Out
Scrum and Waterfall are two different project management methodologies. Scrum is more flexible and is great for a constantly changing environment. Waterfall is more structured and works well for projects you can predict from start to finish. Choose the methodology that best fits your project, team, and industry standards.
I’ve seen both methodologies work successfully when used in the right context. So, there is no one-size-fits-all methodology. Use the methodology that best fits your situation, and don’t be afraid to mix and match.
