PSM I cheat sheet: Professional Scrum Master I

Scrum theory and values

Empiricism rests on three pillars: transparency (the process and work are visible to those responsible for the outcome), inspection (frequent, diligent checking for undesirable variance), and adaptation (adjusting as soon as possible when something's off).
Scrum is built on empiricism and lean thinking together — lean thinking specifically means reducing waste and focusing on the essentials.
The five Scrum values: Commitment, Focus, Openness, Respect, Courage. When genuinely lived by the Scrum Team, they bring the pillars of empiricism to life and build trust.
Scrum is described as a lightweight framework — deliberately incomplete, leaving room for other practices, but with its roles, events, artifacts, and rules held as immutable.

One Scrum Master, one Product Owner, and the Developers — no sub-teams or hierarchies, typically 10 or fewer people to stay nimble.
The Product Owner is one person accountable for maximizing the value of the product, primarily through effective Product Backlog management — they may delegate the work but remain accountable.
The Developers are accountable for creating the Sprint plan (Sprint Backlog), instilling quality via the Definition of Done, adapting their plan daily, and holding each other accountable as professionals.
The Scrum Master serves three groups: the Scrum Team (coaching self-management and cross-functionality), the Product Owner (backlog techniques, stakeholder understanding), and the organization (leading and coaching Scrum adoption) — and is accountable for the Scrum Team's effectiveness.

The Sprint is the container for all the other events — a fixed-length event of one month or less; a new Sprint starts immediately once the previous one ends.
Sprint Planning (max 8 hours for a one-month Sprint) addresses Why the Sprint is valuable, What can be Done, and How the chosen work will get done.
The Daily Scrum (15 minutes, every working day) is internal to the Developers — inspecting progress toward the Sprint Goal and adapting the Sprint Backlog.
The Sprint Review (max 4 hours) is a working session, not a status presentation, involving the Scrum Team and stakeholders. The Sprint Retrospective (max 3 hours) concludes the Sprint, inspecting individuals, interactions, processes, tools, and the Definition of Done.

Product Backlog (commitment: the Product Goal) — an emergent, ordered list of everything needed to improve the product; never complete.
Sprint Backlog (commitment: the Sprint Goal) — the Sprint Goal, the selected items, and the delivery plan, belonging solely to the Developers; the Sprint Goal doesn't change during the Sprint.
Increment (commitment: the Definition of Done) — work only counts as part of the Increment once it meets the Definition of Done; work that doesn't returns to the Product Backlog.
Multiple Increments may be created within a single Sprint, and the Increment can be delivered to stakeholders before the Sprint Review — the Review is never considered a gate to releasing value.

The Definition of Done is a formal, shared quality standard — if an organizational standard exists, every Scrum Team must follow it as a minimum; otherwise the Scrum Team creates one appropriate for the product.
Work cannot be considered part of the Increment unless it meets the Definition of Done — no exceptions, no partial credit for 'mostly done.'
Each new Increment is additive to all prior Increments and thoroughly verified, ensuring they all work together.
The Definition of Done can evolve to become more stringent over time as a product and organization mature — it isn't fixed forever the moment it's first written.

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