Scrum and Kanban are popular agile frameworks, but they differ primarily in their structure and focus. While both aim to improve efficiency and responsiveness, Scrum is a framework that provides a set structure with defined roles, events, and artifacts, whereas Kanban is a method focused on visualizing and optimizing workflow.
Scrum and Kanban offer distinct approaches to project management and team collaboration, especially within the realm of agile development. Understanding their core differences helps teams choose the most suitable framework for their context or even combine elements of both (Scrumban).
According to the provided summary, "Kanban is a project management framework that relies on visual tasks to manage workflows, while scrum is a project management framework that helps teams structure and manage their work through a set of values, principles, and practices." This highlights the fundamental distinction: Kanban emphasizes the flow of work using visual tools, while Scrum provides a more rigid structure and process.
Key Differences Between Scrum and Kanban
Let's delve deeper into the specific areas where these two frameworks diverge.
Structure and Methodology
- Scrum: Scrum is prescriptive. It defines specific roles (Product Owner, Scrum Master, Development Team), time-boxed events (Sprint Planning, Daily Scrum, Sprint Review, Sprint Retrospective), and required artifacts (Product Backlog, Sprint Backlog, Increment). Work is done in fixed-length iterations called Sprints, typically 1-4 weeks long. The emphasis is on building cross-functional, self-organizing teams that deliver potentially shippable product increments at the end of each Sprint.
- Kanban: Kanban is less prescriptive and more evolutionary. It starts with what you do now and aims for continuous improvement. Its core practices include:
- Visualizing the workflow (often on a Kanban board with columns like "To Do," "Doing," "Done").
- Limiting Work in Progress (WIP).
- Managing Flow.
- Making process policies explicit.
- Implementing feedback loops.
- Improving collaboratively.
The focus is on optimizing the flow of value through the system.
Focus and Goals
- Scrum: Focuses on delivering working software frequently and predictably through iterative development cycles (Sprints). It is often used for complex product development where requirements may evolve.
- Kanban: Focuses on improving flow efficiency, reducing cycle time (the time it takes for a work item to move from start to finish), and managing work based on capacity. It's ideal for continuous delivery scenarios, maintenance, or workflows with irregular arrivals of work.
Change Management
- Scrum: Changes are typically incorporated at the start of a new Sprint. Once a Sprint begins, the Sprint Goal and the Sprint Backlog should remain stable to ensure focus and deliverability within the timebox.
- Kanban: Changes can be introduced at any time, provided there is capacity in the system (respecting WIP limits). The focus is on pulling work through the system as capacity becomes available.
Visual Aids
While both may use boards, their primary purpose differs:
- Scrum Board: Often visualizes the work within a single Sprint.
- Kanban Board: Visualizes the entire workflow and helps identify bottlenecks and manage flow. This is where Kanban "relies on visual tasks to manage workflows."
Comparing Scrum and Kanban
Here's a summary of the key distinctions:
| Feature | Scrum | Kanban |
|---|---|---|
| Primary Focus | Structured iterations (Sprints), predictable delivery | Visualizing & optimizing continuous workflow |
| Methodology | Prescriptive roles, events, artifacts | Evolutionary, based on principles & practices |
| Cadence | Fixed-length Sprints | Continuous flow, no fixed iterations |
| Change | Changes primarily at Sprint boundaries | Changes can be introduced as needed (WIP permitting) |
| Team Roles | Specific (PO, SM, Dev Team) | No prescribed roles (teams evolve their own) |
| Metrics | Velocity, Sprint Burndown | Lead Time, Cycle Time, WIP (Work in Progress) |
| Ideal For | Product development, complex projects | Maintenance, support, continuous delivery, stable teams |
Practical Insights
- A team starting a new product from scratch with evolving requirements might find the iterative and structured nature of Scrum beneficial for managing uncertainty and delivering increments regularly.
- A team managing an IT support queue with a constant, unpredictable stream of incoming requests would likely benefit from Kanban's focus on managing flow, limiting WIP, and reducing response time.
Ultimately, the choice between Scrum and Kanban depends on the team's specific needs, project type, organizational culture, and desired outcomes. Many teams even adopt a hybrid approach, taking practices from both frameworks to create what works best for them.
