2.1 The Developers Accountability & Technical Ownership

2.1 The Developers Accountability & Technical Ownership

Scrum Guide 2020 Definition: 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 are often broad and vary with the domain of work.

In traditional software development and project management paradigms, the term "developer" often refers strictly to programmers or software engineers who write source code. In Scrum, however, "Developers" represents a formal accountability that encompasses all team members who actively contribute to building a usable Increment during the Sprint. Whether an individual specializes in automated testing, user experience design, database architecture, infrastructure engineering, security compliance, or business domain analysis, if they participate in creating the Sprint's usable deliverable, they act as Developers.

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Core Accountabilities of Developers

The 2020 Scrum Guide explicitly outlines four foundational accountabilities for Developers. Every candidate preparing for the Professional Scrum Master I (PSM I) examination must thoroughly master these responsibilities and understand their practical application in empirical environments:

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Technical Ownership and Estimation Authority

One of the most heavily tested subject areas on the PSM I examination centers around estimation authority and technical decision-making.

Who Estimates Product Backlog Items?

The Scrum Guide establishes a clear principle: The Developers who will perform the work are solely responsible for sizing and estimating Product Backlog items (PBIs).

• Product Owner Role: The Product Owner helps the team understand requirements, clarifies customer value, and negotiates scope trade-offs. However, the Product Owner cannot assign effort estimates, mandate velocity, or override the Developers' sizing decisions.
• Scrum Master Role: The Scrum Master coaches the team on estimation techniques (such as Story Points, Planning Poker, or T-shirt sizing) and ensures discussions remain productive. However, the Scrum Master never estimates backlog items or assigns work.
• Management Role: External directors, managers, and project management offices (PMOs) have zero authority to dictate estimates or pressure Developers into accepting unrealistic workloads.

Designing, Building, and Testing

Developers possess complete autonomy regarding how to transform selected Product Backlog items into usable Increments. They design system architecture, establish coding and engineering guidelines, implement solution components, and perform comprehensive testing. If technical debt accumulates, Developers are responsible for making this debt transparent to the Product Owner and incorporating remediation tasks into the Sprint Backlog.

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Elimination of Titles and Sub-Teams

To foster genuine collaboration, mutual trust, and collective ownership, Scrum enforces strict structural rules regarding team composition:

1. No Individual Titles: Within the Developers, no individual titles are recognized (such as "Lead Software Architect," "Senior QA Automation Lead," or "UI/UX Specialist"). While team members naturally possess specialized skills and deep domain expertise, everyone is recognized simply as a Developer.
2. No Sub-Teams: Scrum explicitly forbids sub-teams within the Scrum Team (such as a separate "Testing Sub-Team," "Architecture Sub-Team," or "Hardening Group"). All capabilities required to bring an item from the Product Backlog to a finished Increment must exist within the single, unified Scrum Team.
3. Collective Accountability: If a critical bug slips into production or a Sprint Goal is missed, accountability falls on the Developers collectively and the Scrum Team as a whole—never on an individual tester, designer, or developer.

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Sizing the Developers and Scrum Team

Communication overhead increases exponentially as team size expands. To maintain agility, high performance, and effective collaboration, Scrum defines optimal team size boundaries:

• Total Team Size: The Scrum Team—comprising the Product Owner, Scrum Master, and Developers—should generally consist of 10 or fewer people.
• Benefits of Small Teams: Small teams communicate more efficiently, build deeper interpersonal trust, exhibit higher flexibility, and experience significantly less administrative overhead.
• Handling Large Products: If a product requires more capacity than a single 10-person team can provide, the organization should split into multiple parallel Scrum Teams. All such teams focus on the exact same Product Goal, share a single Product Backlog, and align through a single Product Owner.

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Real-World Exam Traps for Developers

To score highly on the PSM I assessment, candidates must easily identify anti-patterns that violate Scrum principles:

Trap 1: The Product Owner Dictates Work Volume

Incorrect Scenario: The Product Owner demands that Developers accept 15 user stories into the Sprint Backlog to meet a quarterly executive milestone. Correct Scrum Behavior: The Developers evaluate their own capacity, review the prioritized Product Backlog, and decide how many items they can realistically pull into the Sprint while maintaining quality and achieving the Sprint Goal.

Trap 2: Quality Sacrificed for Speed

Incorrect Scenario: As the Sprint timebox nears its end, Developers decide to skip automated regression testing and technical documentation so all items can be marked finished. Correct Scrum Behavior: Items that fail to meet the Definition of Done cannot be considered done or demonstrated at the Sprint Review. They remain incomplete and return to the Product Backlog.

Trap 3: The Daily Scrum as a Management Status Meeting

Incorrect Scenario: Developers stand in front of the Scrum Master or a Project Manager to answer individual status questions. Correct Scrum Behavior: Developers conduct the Daily Scrum amongst themselves, inspecting progress toward the Sprint Goal and adjusting their daily work plan for the next 24 hours.

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Summary Checklist for PSM I Candidates

• Developers own the Sprint Backlog, technical implementation, quality standards, and work estimates.
• No titles or sub-teams exist within the Developers; accountability is shared collectively.
• The team size for a Scrum Team is typically 10 or fewer people.
• The Daily Scrum is owned by Developers to adapt their plan toward the Sprint Goal.