Project Toolkit

Project Resources / OBS

Project Resources / OBS

Understanding the Organisational Breakdown Structure and resource organisation.

Project Resources & OBS

The Organisational Breakdown Structure (OBS) defines how resources are organised within the project.

What is an OBS?

Definition: The Organisational Breakdown Structure (OBS) is a hierarchical representation of project resources organised by team, function, or department.

OBS vs WBS

OBS WBS
Shows who does the work Shows what work is done
Organised by resource/team Organised by deliverable
Answers “who is responsible?” Answers “what will be delivered?”

When OBS and WBS intersect, you can assign accountability for each deliverable.

Example OBS Structure

flowchart LR PM[Project
Manager] --> TL1[Development
Lead] PM --> TL2[Test
Lead] PM --> TL3[BA
Lead] TL1 --> D1[Developer 1] TL1 --> D2[Developer 2] TL2 --> T1[Tester 1] TL3 --> BA1[BA 1] classDef blue fill:#108BB9,stroke:none,color:#fff class PM,TL1,TL2,TL3,D1,D2,T1,BA1 blue

Resource Types

Type Description Examples
Internal Organisation employees Staff, secondees
External External resources Contractors, consultants
Shared Shared with other work Part-time resources
Specialist Specific expertise Architects, security

Resource Information

Capture for each resource:

Field Description
Name Resource identifier
Role Position on project
Skills Relevant capabilities
Availability % time on project
Start/End Duration on project
Cost Day rate or salary allocation
Reporting line Who they report to

Responsibility Assignment

Use a RACI matrix to link OBS and WBS:

  PM Dev Lead BA Tester
Requirements A C R I
Design A R C I
Build A R I I
Test A C I R
  • R = Responsible (does the work)
  • A = Accountable (owns the outcome)
  • C = Consulted (provides input)
  • I = Informed (kept up to date)

Resource Planning Considerations

Factor Questions
Skills Do we have the right capabilities?
Capacity Is there enough time available?
Availability When are resources available?
Location Where are resources based?
Cost What is the budget impact?
Dependencies What other demands exist?

Common Challenges

Challenge Mitigation
Resource conflicts Early planning, clear priorities
Skill gaps Training, recruitment, contractors
Turnover Knowledge transfer, documentation
Over-allocation Realistic planning, monitoring
Availability changes Contingency planning

Resource Checklist

  • OBS defined?
  • Resource requirements identified?
  • Roles and responsibilities clear?
  • RACI matrix completed?
  • Availability confirmed?
  • Costs captured?
  • Reporting lines established?
Last updated: 13 January 2026
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People

OBS

Organisational Breakdown Structure