Agile, Scrum, Kanban, and Lean: A Detailed Comparison
Agile
Agile is a broad philosophy that emphasizes collaboration, flexibility, and continuous improvement. It provides a way to manage projects and improve processes.
Scrum
Scrum is a framework within the Agile methodology for managing projects. It offers a structured way to “do Agile.” Teams work in short blocks called sprints (typically 2-4 weeks). Each sprint has clear goals, and the team reviews progress at the end. Scrum has three roles:
- Product Owner: Decides what needs to be done.
- Scrum Master: Ensures the team follows Scrum and removes obstacles.
- Development Team: Does the actual work.
Kanban
Kanban is a visual method for managing work by tracking tasks on a board. It focuses on moving tasks through stages, typically: “To Do,” “Work in Progress,” and “Done.” The “Done” stage is defined by the team, usually when a product is ready for presentation or feedback. Kanban helps limit the number of tasks in progress at any time to avoid bottlenecks. Its four key values are:
- Start with what you are doing now.
- Agree to pursue incremental and evolutionary changes.
- Respect current roles, job titles, and responsibilities.
- Encourage acts of leadership at all levels.
Businesses favor Kanban because it is non-disruptive, improves flow, reduces resistance, and encourages collaboration. Its five goals are:
- Planning flexibility
- Reducing bottlenecks
- Shorter time cycles
- Visual metrics
- Continuous delivery
Kanban’s six principles are:
- Visualize the flow of work.
- Limit Work in Progress (WIP).
- Manage flow.
- Make process policies explicit.
- Implement feedback loops.
- Improve collaboratively and evolve experimentally using the scientific method.
Lean
Lean is a broader philosophy aimed at maximizing value and minimizing waste in processes. It focuses on what truly matters to the customer, cuts unnecessary steps, and improves efficiency. Lean’s five principles are:
- Define customer value.
- Map the value stream.
- Create flow.
- Establish pull.
- Pursue perfection.
There are eight types of waste in Lean:
- Transport
- Motion
- Skills
- Inventory
- Defects
- Overproduction
- Overprocessing
- Waiting
Key Roles in Scrum
Scrum Master
The Scrum Master is a facilitator for an Agile development team. They are responsible for managing the exchange of information and collaboration between team members. Their duties include keeping everyone on track, helping the Product Owner, supporting the team, and handling outside distractions or interruptions. The Scrum Master ensures a smooth project, handles changes, and guides the Scrum process.
Product Owner
The Product Owner is the team’s decision-maker and planner for what gets built. They ensure the team is working on the right things that matter most to the customer. Their duties include managing the Product Backlog, planning the work, and representing stakeholders. They do not manage people or do the actual work; instead, they focus on what needs to be done and why. The Product Owner keeps the team focused on the most important features and ensures they deliver products that customers love.
Development Team
The Development Team is a group of skilled workers responsible for building the product in Scrum. They turn ideas into realities. Their duties include building the product, self-organizing, collaborating as equals, and supporting each other. The Development Team is cross-functional, meaning they have all the skills needed to complete the project. They take ownership of their work and work at a steady, sustainable pace.
Scrum Ceremonies
Scrum ceremonies are structured meetings designed to ensure alignment, collaboration, and efficiency in Agile projects. They emphasize clear communication while minimizing unnecessary or unproductive meetings. Each ceremony follows a specific format and duration, ensuring the team stays focused on their goals.
Sprint
A Sprint is a fixed time frame, usually one to four weeks, during which the team works on specific tasks to deliver a “Done” version of the product for feedback. The length of Sprints remains consistent throughout the project. Changes to tasks during a Sprint are discouraged to avoid stress and ensure quality. Each Sprint begins immediately after the previous one concludes, creating a cycle of continuous progress and refinement.
Sprint Planning
Sprint Planning marks the start of each Sprint. The team, along with the Scrum Master and Product Owner, decides on the Sprint Goals and determines how to achieve them. The Product Owner brings a prioritized Product Backlog, and the team selects tasks based on capacity and past performance. Once agreed, tasks are added to the Sprint Backlog.
Daily Scrum
Daily Scrum meetings, or stand-ups, are brief sessions where the team discusses progress, plans for the day, and any obstacles. These meetings improve communication and keep the team aligned toward the Sprint Goal.
Sprint Review
At the end of a Sprint, the Sprint Review is held. Here, the team presents the “Done” product increment to stakeholders for feedback. This ceremony ensures the project stays on track and aligns with stakeholder expectations. Changes or new requirements may be added to the Product Backlog during this time.
Sprint Retrospective
Finally, the Sprint Retrospective allows the team to reflect on their performance during the Sprint. They discuss what went well, what didn’t, and how to improve for the next Sprint. This process fosters continuous improvement in teamwork, tools, and practices.
Overall, Scrum ceremonies provide a structured framework to ensure productive collaboration and continuous delivery of high-quality products.
Scrum Artifacts
Scrum artifacts are essential tools used in the Scrum framework to organize work, track progress, and keep the team and stakeholders aligned. They simplify the management of product development by focusing on just enough documentation to be useful without becoming overwhelming.
Product Backlog
The Product Backlog is the starting point for the entire project. It’s a dynamic, evolving list of everything the product needs to meet its goals, such as features, fixes, enhancements, and other requirements. The Product Owner is responsible for creating and maintaining this list. It’s not static—new items can be added at any time as priorities shift or stakeholders suggest changes. Items are organized by priority, so the team knows what to focus on next. Think of it as a master to-do list that remains flexible and grows or shrinks as the project evolves. For example, a Product Backlog for a website project might start with basic features like a homepage and navigation, but as development progresses, more complex requirements, like product pages or user accounts, can be added.
Sprint Backlog
The Sprint Backlog is a subset of the Product Backlog, created by the Development Team at the start of each Sprint. This list includes the tasks the team commits to completing during the Sprint. Unlike the Product Backlog, the Sprint Backlog is focused and time-bound, helping the team achieve their Sprint Goal. Every day, during Daily Scrums, the team reviews the Sprint Backlog to discuss progress, plan the day, and adjust if needed. The Sprint Backlog can change slightly during the Sprint if new work emerges, but it’s mainly a tool to keep the team focused on their immediate objectives.
Both artifacts serve distinct but complementary purposes. The Product Backlog provides a high-level view of the entire project, ensuring that the team and stakeholders know what’s coming next and can adapt to changes. The Sprint Backlog zooms in on what’s currently being worked on, offering a clear guide for the team to complete tasks efficiently and stay aligned.
These tools are crucial for measuring progress. By comparing the work completed against what’s left in the Product Backlog, the team and stakeholders can gauge how much closer they are to the project’s goals. Similarly, tracking daily progress with the Sprint Backlog ensures the team stays on schedule and can adapt to any challenges that arise. Together, these artifacts make Scrum projects manageable, transparent, and adaptable to change.
Agile vs. Lean
Agile and Lean are two methodologies that focus on improving processes and delivering value efficiently, but they differ in their origins, principles, and areas of application. Lean originated in manufacturing, particularly from Toyota’s Production System, and was designed to optimize production by eliminating waste and ensuring value for the customer. Over time, it expanded beyond manufacturing and is now used in various industries to improve workflows and reduce inefficiencies.
Agile, on the other hand, emerged in the software development world with the Agile Manifesto in 2001. It was created as a response to rigid project management methods that often led to delays and misaligned outcomes. Agile emphasizes adaptability, collaboration, and iterative delivery, making it particularly suitable for projects where requirements are constantly evolving.
The primary focus of Lean is on the entire process. It seeks to create a smooth and predictable flow of work by eliminating unnecessary steps, ensuring consistent quality, and continuously improving operations. Tools like Kanban boards and value stream mapping are often used to visualize workflows and identify bottlenecks. Lean measures success through efficiency and waste reduction, striving to maximize output with minimal resources.
Agile centers on managing teams and projects in dynamic environments. It operates through short cycles of work, called iterations or sprints, where teams deliver small, functional pieces of a product frequently. Agile prioritizes individuals, collaboration, and customer feedback over rigid processes or extensive documentation. Progress is often measured by the delivery of usable and valuable results, with teams regularly reflecting on their performance and making adjustments to improve.
While Lean focuses on optimizing systems and processes across an organization, Agile is more about empowering teams to work effectively in unpredictable conditions. Despite their differences, the two approaches share common values, such as prioritizing customer satisfaction and promoting continuous improvement. They are sometimes combined to leverage the strengths of both methodologies, particularly in industries where adaptability and efficiency are equally important.
Scrum vs. Kanban
Scrum and Kanban are both frameworks that help teams work more efficiently and deliver value, but they have different structures and approaches to managing work. Scrum is a framework that divides work into fixed-length iterations, called Sprints, which typically last two to four weeks. Each Sprint starts with planning, where the team selects a set of tasks to complete, and ends with a review, where they demonstrate what they’ve accomplished. Scrum includes roles like the Product Owner, Scrum Master, and Development Team, and it has specific ceremonies, such as Sprint Planning, Daily Standups, Sprint Review, and Sprint Retrospective, which help the team stay aligned and continuously improve.
In contrast, Kanban is a more flexible and visual framework that focuses on continuous flow rather than iterations. Kanban doesn’t have defined roles or time-boxed events. Instead, it uses a visual board, called a Kanban board, to track tasks and their progress across columns, such as “To Do,” “In Progress,” and “Done.” This visual tool allows teams to see bottlenecks and areas where work is piling up, enabling them to focus on optimizing flow and eliminating delays. Kanban also emphasizes limiting the work in progress (WIP) to prevent teams from taking on too many tasks at once, which helps improve focus and reduces multitasking.
The main difference between Scrum and Kanban lies in their approach to structure and workflow. Scrum works in time-boxed iterations with a fixed set of tasks, and there’s a stronger emphasis on roles and ceremonies to ensure the team remains organized and on track. Kanban, on the other hand, is more flexible, with an ongoing flow of work that isn’t tied to fixed time periods. There are no set roles or ceremonies, making it easier to implement in teams with more varied or less structured processes.
While Scrum is best suited for teams that thrive with structured schedules and clear goals for each iteration, Kanban works well for teams that need flexibility, especially when work arrives in an unpredictable or continuous manner. Both methodologies aim to increase efficiency and improve workflow, but Scrum is more focused on delivering work in chunks with regular reviews, while Kanban focuses on optimizing the continuous flow of work without fixed iterations. In some cases, teams combine elements of both frameworks to suit their needs.