Scrum
Overview
Scrum is an agile framework for developing complex products. It is used particularly often in software development and is based on short iterations called sprints, clear roles, and regular reflection.
The 3 roles
A Scrum team consists of one Product Owner, one Scrum Master, and the Developers. It typically has 10 or fewer members and no sub-teams or hierarchies. These roles are also called accountabilities.
Product Owner (PO)
The Product Owner is the single person responsible for the product. They represent the interests of stakeholders.
Tasks:
- Maintains and prioritizes the product backlog
- Defines requirements (user stories)
- Decides what will be built
- Tests results
Scrum Master
The Scrum Master is responsible for the process itself. They are not a traditional manager but a servant leader.
Tasks:
- Ensures that Scrum is applied correctly
- Removes obstacles (impediments)
- Coaches the team
- Moderates meetings
Developers
The Developers are the people in the Scrum team who implement the requirements. The Scrum team is self-managing: it decides internally who does what, when, and how, without being directed by outsiders.
- Cross-functional
- Create the sprint backlog
- Create at least one usable increment per sprint
The 5 events
Sprint
A sprint is a fixed time period during which the team works on a set of tasks. It is the heartbeat of Scrum, providing a regular rhythm for planning, building, and reviewing work.
- Duration: 1 month at most (commonly 2-4 weeks)
- Goal: Finished, usable increment
Important: During a sprint, no changes that jeopardize the sprint goal should be introduced.
Sprint Planning
At the beginning of each sprint, the entire Scrum team meets to decide what work will be taken on. The team selects items from the product backlog and creates a plan for how to deliver them.
Result:
- Sprint Goal
- Sprint Backlog
Daily Scrum / Daily Standup
The Daily Scrum is a short synchronization meeting where the Developers align on progress and identify blockers. It is also called a "standup" because participants often stand during the meeting to encourage brevity and ensure the 15-minute timebox is respected.
- Duration: 15 minutes
- Participants: Developers
No fixed structure is prescribed. Three questions are common:
- What did I do yesterday?
- What am I doing today?
- Are there any obstacles?
Sprint Review
At the end of each sprint, the team presents the finished increment to stakeholders. The purpose is to gather feedback and collaboratively decide on the next steps for the product.
- Presentation of results
- Feedback from stakeholders
- Adjustment of the product backlog
Sprint Retrospective (Retro)
The retrospective is an internal meeting for the Scrum team to reflect on the past sprint. The goal is to identify concrete improvements for the next sprint, making this the key event for continuous improvement.
Typical questions:
- What went well?
- What went badly?
- How can we improve?
The 3 artifacts
Each artifact has a commitment against which its progress is measured: the product backlog has the product goal, the sprint backlog the sprint goal, and the increment the Definition of Done.
Product Backlog
The product backlog is the single source of truth for all work that needs to be done on the product. It is a living document that evolves as the product and its environment change.
- A prioritized list of all requirements
- Maintained by the Product Owner
- Entries mostly in the form of user stories (e.g. "As a user, I want X so that Y")
Sprint Backlog
The sprint backlog contains the subset of the product backlog selected for the current sprint, the sprint goal, and a plan for delivering the selected items.
- Filled with tasks for the current sprint
- Created by the Developers
- Concrete and feasible
Increment
An increment is a concrete step toward the product goal and adds to all previous increments. Several increments can be created within one sprint, and their sum is presented at the sprint review. Each increment must be in a usable state regardless of whether the Product Owner decides to release it.
- Finished, tested product component
- Must comply with the Definition of Done (DoD)
Important terms
Definition of Done (DoD)
The Definition of Done is a shared agreement within the team that defines clear criteria for when a backlog item is considered "finished." It ensures consistent quality and prevents incomplete work from being delivered.
Example:
- Code written
- Tests green
- Review conducted
- Documentation updated
Product Goal
The product goal describes a future state of the product and serves as the long-term objective of the Scrum team. The Scrum team pursues exactly one product goal at a time. It must be fulfilled or abandoned before the next one is taken on.
Sprint Goal
The sprint goal is an overarching objective that gives the team a shared direction for the sprint. It should describe a meaningful outcome rather than a list of tasks.
Not "complete 5 tickets", but for example:
- "Users can register and log in"
- "Users can give feedback with a dedicated button"
Velocity
Velocity measures the average number of story points a team completes per sprint. It is used as a planning tool to forecast how much work can realistically be taken on in future sprints. It is not a tool for ranking performance.
Story Points
Story points are a relative unit of estimation used to express the overall effort needed to implement a backlog item. Rather than estimating in hours, teams compare items against each other.
- Often Fibonacci (1, 2, 3, 5, 8, 13, ...)
- Takes into account complexity, risk, and effort
Typical sprint process
- Sprint Planning
- Development + Daily Standups
- Sprint Review
- Sprint Retro
- New sprint
Pros and cons of Scrum
Pros
- Fast delivery of value
- High flexibility
- Early feedback through stakeholders
- Transparency
- Continuous improvement
Cons
In practice, Scrum is often implemented incorrectly. This leads to common anti-patterns:
- Misunderstood role of the Product Owner
- Scrum Master as a "mini-boss"
- Daily as a long status meeting for managers
- No real self-management
- "We do Scrum, but..."
Difference from traditional project management (e.g. waterfall model)
| Waterfall | Scrum |
|---|---|
| Fixed planning at the beginning | Iterative approach |
| Changes are expensive | Changes are planned for |
| One delivery | Regular updates through increments |
| Strong hierarchy | Self-managing |