Dunbar's Number

Dunbar's Number
Image: Jono Hey, Sketchplanations

Dunbar's Number suggests that humans can maintain stable social relationships with about 150 individuals (rounded up from 148). This number represents the maximum number of people with who one can have meaningful interactions and a sense of community. Two-thirds of our time is spent with the closest twenty people and the other third with the rest. Beyond this limit, the quality of relationships tend to decline due to cognitive and time constraints.

In the context of Agile teams, Dunbar's Number influences how teams and organizations should structure themselves to maximize efficiency, collaboration, and communication.

  • Optimal Team and Group Sizes:
    • Small Cross-Functional Teams:
      • Agile frameworks and methodologies recommend team sizes of around 5 to 12 members (depending on the methodology).
      • Keeping teams small enhances communication and allows members to form strong working relationships
    • Scasled Agile Framework (SAFe) Agile Release Trains (ARTs):
      • An ART contains about 5-12 Agile Teams.
      • Around 150 people or less per ART.
  • Communication and Coordination:
    • Efficient Information Flow:
      • By keeping groups within the cognitive limit proposed by Dunbar's Number, it ensures that communication remains manageable, reducing the risk of misunderstandings and information overload.
  • Organizational Structure:
    • Alignment and Cohesion:
      • Within the constraints of Dunbar's Number, teams and ARTs can develop a shared vision and culture, which is crucial for alignment in large-scale Agile implementations.
    • Community Building:
      • Building communities that foster relationships within groups that do not exceed Dunbar's Number.
  • Scaling Challenges and Solutions:
    • Managing Complexity:
      • As organizations grow, SAFe uses Dunbar's Number to guide the scaling process, ensuring that each layer of the framework does not exceed the cognitive capacity for maintaining relationships.
    • Lean-Agile Leadership:
      • Leaders are trained to manage within these group sizes to sustain agility and responsiveness.

Scenario

An enterprise is adopting SAFe to scale Agile practices across multiple departments. The organization consists of 600 employees involved in product development. They need to structure their teams to maximize efficiency, communication, and alignment with SAFe principles.

Application of Dunbar's Number in SAFe:

  1. Formation of Agile Release Trains (ARTs):
    • Organization forms 6 ARTs consisting of 5-12 Agile teams.
    • Each Agile team contains 5-12 members.
    • The size of each ART is within Dunbar's Number, allowing team members to build meaningful relationships within their ART.
  2. Communication within ARTs:
    • PI Planning
      • Every 8-12 weeks, each ART conducts PI Planning bringing together all members to plan and align on objectives.
      • With around or less than 150 people, each ART will have manageable events, and everyone can actively participate.
    • ART Syncs
      • Regular synchronization meetings are held to coordinate among teams within the ART.
      • The manageable group size ensures effective communication and swift decision-making.
  3. Cross-ART Coordination:
    • For large solutions requiring multiple ARTs, SAFe introduces Solution Trains.
    • Even at this level, SAFe recommends keeping the group sizes within a range that doesn't exceed Dunbar's Number, often by creating additional layers of coordination without involving everyone directly.
  4. Building a Shared Culture:
    • Communities of Practice
      • These groups bring together individuals across different ARTs who share common roles or interests (e.g., Scrum Masters, Product Owners, DevOps).
      • By keeping these communities within Dunbar's Number, members can effectively share knowledge and practices.
    • Lean-Agile Mindset
      • Leaders promote a culture of trust, collaboration, and continuous improvement.
      • Smaller group sizes facilitate the adoption of shared values and principles.

Outcomes:

  • Enhanced Communication and Collaboration:
    • Team members within each ART develop strong working relationships.
    • Efficient communication channels lead to fewer misunderstandings and quicker problem resolution.
  • Effective Scaling:
    • By respecting Dunbar's Number, the organization scales its Agile practices without overcomplicating communication.
    • The structure allows for Agility and responsiveness at scale.
  • Strong Organizational Culture:
    • Each ART cultivates its own identify while aligning with the organization's overarching goals.
    • Employees feel connected and engaged, boosting morale and productivity.

Challenges & Mitigation Strategies

While applying Dunbar's Number within SAFe brings numerous benefits, challenges can arise:

  • Inter-ART Coordination:
    • Challenge:
      • Coordinating work across multiple ARTs can become complex.
    • Mitigation:
      • Use Solution Trains to manage large-scale coordination.
      • Implement System Demos and Inspect & Adapt workshops to ensure alignment.
  • Maintaining Alignment:
    • Challenge:
      • Ensuring all ARTs align with the organization's strategic objectives.
    • Mitigation:
      • Establish a Portfolio Level in SAFe to provide governance and alignment.
      • Use Lean Portfolio Management to connect strategy to execution.
  • Cultural Consistency:
    • Challenge:
      • Different ARTs may develop varying cultures that could diverge.
    • Mitigation:
      • Promote the SAFe Core Values across the organization.
      • Encourage Leadership Engagement to reinforce a unified culture.

Conclusion:

Dunbar's Number significantly impacts agile teams within the Scaled Agile Framework by guiding the optimal size of teams and groups to maintain effective communication and relationships.

By structuring teams and ARTs within this cognitive limit, organizations can:

  • Enhance Collaboration:
    • Smaller, well-connected groups foster better teamwork and knowledge sharing.
  • Improve Communication:
    • Manageable group sizes reduce complexity in communication channels.
  • Maintain Agility at Scale:
    • Organizations can scale up without sacrificing the responsiveness and adaptability of smaller teams.
  • Strengthen Culture and Alignment:
    • Teams can develop a shared vision and culture, crucial for cohesive progress towards common goals.

Key Takeaways for Agile Teams Using SAFe

  1. Optimize Team and ART Sizes:
    • Keep agile teams between 5 to 9 members.
    • Structure ARTs to stay within or close to Dunbar's Number.
  2. Facilitate Effective Communication:
    • Use SAFe ceremonies (PI Planning, Scrum of Scrums, PO Sync, ART Sync) to ensure alignment.
    • Encourage open, face-to-face communication where possible.
  3. Build Strong Relationships:
    • Promote team-building activities within teams and ARTs.
    • Foster trust and collaboration through shared goals and values.
  4. Implement Structured Coordination Mechanisms:
    • Use SAFe's constructs (Solution Trains, Portfolio Level) to manage larger group coordination without overwhelming communication networks.
  5. Cultivate a Unified Culture:
    • Embed the Lean-Agile mindset throughout the organization.
    • Ensure leadership models desired behaviors and values.

Summary

Applying Dunbar's Number within the Scaled Agile Framework helps organizations balance the benefits of scaling Agile practices with the need to maintain effective communication and strong relationships. By being mindful of cognitive limits and structuring teams accordingly, organizations can achieve greater efficiency, innovation, and employee satisfaction, ultimately leading to successful Agile transformations at scale.