Scrum vs Lean

Abdul Wahid

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ScrumThe term for a strategy in the rugby game that

means ‘getting out-of play ball back into the game’ with team work

Management methodology by Schwaber and Beedle, 2001

Assumes that development process is unpredictable and complex, requiring flexibility and responsive to change

Characteristics: Self-organizing teams Product progresses in a series of month-long “sprints” Requirements are captured as items in a list of “product backlog” No specific engineering practices prescribed

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Lean Software Development

Derived from the Lean Manufacturing (Toyota)

Focuses much more on the project management aspects of software development

Specifically targeting the cost and ROI attributes of a project

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Lean Principles

1. Create nothing but value/ Eliminate Waste2. Build Quality In

Automate as much as possible

3. Create Knowledge Work with business people

4. Defer Commitment Decide as late as possible

5. Deliver Fast6. Respect People7. Optimize the Whole

optimizes the whole value stream, from the time it receives an order to address a customer need until software is deployed and the need is addressed

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Apples to Oranges?

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Apples to Oranges? Comparing Scrum to Lean - Not Quite Apples to

Oranges (alshall) Lean and Scrum are both about improving the software

development capabilities of an organization Scrum and Lean are mindset They have different approaches and they work

effectively in different situations. Scrum starts at the team while Lean starts at the

process. Lean Software Development provides much more

specific hints how to perform tasks and a set of engineering practices, while Scrum restricts itself to a basic framework of project management practice

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Comparison with respect to different aspects

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Scrum vs Lean

Procedures Scrum has few, but well defined meetings, roles, artifacts

Lean consists of practises and more general advices – all starting with the value stream

Team and Responsibilities In Scrum the team is self organized and as a team responsible for the

results. The results are presented to the Product Owner in Sprint reviews who accepts them and represents the business responsibility to the outside world.

Lean also puts much emphasis on developing a team and its initiative and involvement, but there exists also an aspect of leadership – at Toyota in the role of the chief engineer. The chief engineer or champion is ultimately responsible for the results, breaks deadlocks and ensures the results are produced in time.

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Scrum vs Lean

Values Respect People are not resources

Engineering practices Scrum does not contain statements about engineering practices, so it

is easy to add the Lean engineering practices

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Scrum vs Lean

Knowledge Building Scrum has a widely-used practice of retrospectives in teams. While the

retrospective was not part of the original definition of Scrum, it is impossible to imagine today’s Scrum practice without retrospectives. The retrospective is in some sense where teams’ learning takes place. Scrum contains no institutionalized form of spreading knowledge in an organization.

Lean addresses knowledge building in two ways: first, it combines the areas decision making and knowledge building Second, Lean has means to follow up on acquired knowledge:

Iterations / Sprints / Timeboxes Scrum work is done in fixed length iterations called Sprints. Lean is less specific on time boxes. It has a system called Kanban

which ist similar to a product backlog.

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Conclusion

While Scrum and Lean concentrate on different aspects, they both have their main focus on creating value and share fundamental values.

Scrum does not prescribe a specific process, it is a framework which can be extended to a process and many of the Lean principles can be used in doing so where Scrum does not contain a definition.

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Lean References “Lean Software Development: An Agile Toolkit “ by Mary Poppendieck and Tom

Poppendieck Implementing Lean Software Development: From Concept to Cash (The

Addison-Wesley Signature Series) “Implementing Lean Software Development: From Concept to Cash” by Mary

Poppendieck and Tom Poppendieck http://www.poppendieck.com/ “Agile Software Development with Scrum” by Kent Schwaber and Martin Beedle http://www.controlchaos.com http://www.scrumalliance.org http://johannordin.wordpress.com/2008/06/11/comparing-lean-and-scrum-

whats-the-difference http://scrumcenter.org/node/26 http://www.netobjectives.com/blogs/comparing-scrum-to-lean-not-quite-apples-

to-oranges