1.3 The Scrum Team Overview

1.3 The Scrum Team Overview

Official Scrum Guide Definition: The fundamental unit of Scrum is a small team of people, a Scrum Team. The Scrum Team consists of one Scrum Master, one Product Owner, and Developers. Within a Scrum Team, there are no sub-teams or hierarchies. It is a cohesive unit of professionals focused on one objective at a time, the Product Goal.

Understanding the structure, accountabilities, and boundaries of the Scrum Team is critical for PSM I candidates. Scrum eliminates traditional project silos, manager hierarchies, and specialized sub-teams in favor of unified accountability.

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The Three Accountabilities in Scrum

Notice that the 2020 Scrum Guide intentionally uses the term accountabilities rather than "roles". This emphasizes that these responsibilities are non-negotiable core accountabilities required to operate empirically:

                       ┌───────────────────────────────┐
                       │        THE SCRUM TEAM         │
                       │     (Typically ≤ 10 People)   │
                       └───────────────┬───────────────┘
     ┌─────────────────────────────────┼─────────────────────────────────┐
     ▼                                 ▼                                 ▼
PRODUCT OWNER                    SCRUM MASTER                       DEVELOPERS
Accountable for:                 Accountable for:                  Accountable for:
• Maximizing Value               • Scrum Effectiveness             • Usable Increments
• Product Backlog Management     • True Leader Who Serves          • Sprint Backlog Plan
• Product Goal Definition        • Coaching Self-Management        • Adhering to DoD

1. The Product Owner

Accountable for maximizing the value of the product resulting from the work of the Scrum Team. How this is done may vary widely across organizations, but core accountabilities include:

• Developing and explicitly communicating the Product Goal.
• Creating, ordering, and clearly communicating Product Backlog items.
• Ensuring the Product Backlog is transparent, visible, and understood.
• The Product Owner is one person, not a committee. The Product Owner may represent the desires of a committee, but anyone wanting to change the Product Backlog must address the Product Owner.

2. The Scrum Master

Accountable for establishing Scrum as defined in the Scrum Guide and for the Scrum Team's effectiveness. The Scrum Master achieves this by enabling the team to improve its practices within the Scrum framework:

• Serving the Scrum Team by coaching in self-management and cross-functionality.
• Helping the team focus on creating high-value Increments meeting the Definition of Done.
• Causing the removal of impediments to the Scrum Team's progress.
• Serving the Product Owner with backlog management techniques and empirical product planning.
• Serving the organization by leading, training, and coaching Scrum adoption.

3. Developers

Developers are the people in the Scrum Team that are committed to creating any aspect of a usable Increment each Sprint. The specific skills needed by the Developers vary with the domain of work, but they are always accountable for:

• Creating a plan for the Sprint, the Sprint Backlog.
• Instilling quality by adhering to a Definition of Done.
• Adapting their plan each day toward the Sprint Goal.
• Holding each other accountable as professionals.

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Key Core Properties of a Scrum Team

Property 1: Cross-Functionality

Scrum Teams are cross-functional, meaning the members have all the skills necessary to create value each Sprint without depending on outside assistance.

• The team includes developers, testers, UX designers, database specialists, system architects, and analysts as needed.
• Exam Trap: There are no separate "QA Teams" or "UX Teams" inside or outside Scrum. Testing and design are activities performed by the Developers within the cross-functional Scrum Team.

Property 2: Self-Management (2020 Scrum Guide Shift)

Scrum Teams are self-managing, meaning they internally decide who does what, when, and how.

• Historical Distinction: In the 2017 Scrum Guide, teams were called "self-organizing" (deciding how to do work). The 2020 guide upgraded this to "self-managing" (deciding who, what, when, and how).
• Management or Scrum Masters do not assign tasks to team members. Developers pull work from the Sprint Backlog self-manageably.

Property 3: Small Team Size (10 or Fewer People)

Scrum Teams are small enough to remain nimble and large enough to complete significant work within a Sprint, typically 10 or fewer people.

• Why 10 or fewer? As team size grows, the number of communication channels increases exponentially according to the formula: $\text{Communication Channels} = \frac{N(N - 1)}{2}$ For a team of 6 people, there are 15 channels. For a team of 15 people, there are 105 channels! Smaller teams communicate better and manage work more effectively.

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Structuring Multiple Scrum Teams on a Single Product

If a product is large and requires more than 10 developers, you should split the team into multiple smaller Scrum Teams. When multiple teams work on the same product:

• They must share the SAME Product Goal.
• They must share the SAME single Product Backlog.
• They must share the SAME single Product Owner.
• Each team has its own Scrum Master and its own Developers.
• All teams must produce an integrated, usable Increment at the end of every Sprint that meets a shared Definition of Done.

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Comparison Table: Scrum Accountabilities vs. Traditional Roles