Craig Larman and Bas Vodde outline what Large-Scale Scrum (LeSS) is, its background, and how it can help you scale agility in large organizations.
a large story map in initial PBR in LeSS
Scrum is an empirical-process-control development framework in which a cross-functional self-managing Team develops a product in an iterative incremental manner.1 Each timeboxed Sprint, a potentially shippable product increment is delivered and, ideally, shipped. A single Product Owner is responsible for maximizing product value, prioritizing items in the Product Backlog, and adaptively deciding the goal of each Sprint based on constant feedback and learning. A small Team is responsible for delivering the Sprint goal; there are no limiting single-specialized roles. A Scrum Master teaches why Scrum and how to derive value with it, coaches the Product Owner, Team, and organization to apply it, and acts as a mirror. There is no project manager or team lead.
Empirical process control requires transparency, which comes from short-cycle development and review of shippable product increments. It emphasizes continuous learning, inspection, and adaptation about the product and how it’s created. It’s based on understanding that in development things are too complex and dynamic for detailed and formulaic process recipes, which inhibit questioning, engagement, improvement.
In the Scrum Guide and Scrum Primer, the emphasis is for one Team; the focus is not many Teams working together. And that naturally leads to thinking about large-scale Scrum.