In IFS, the WBS (Work Breakdown Structure) and the CBS (Cost Breakdown Structure) are two core hierarchical structures used to manage different aspects of projects. They are not alternatives to each other; they can also be used together.
| WBS — Work Breakdown Structure | CBS — Cost Breakdown Structure | |
|---|---|---|
| Focus | Planning, executing and tracking the scope of work | Controlling costs and revenues |
| Use | The operational backbone of the project | Optional; in the Project Budgeting and Forecasting module |
| Scheduling | Yes | No |
| Typical elements | Project, sub-project, activity, milestone, task | Material, labour, sub-contract, plant, expenses |
Core focus and purpose
The WBS is used to plan, execute and track the progress of the agreed scope of work. It organises the project into logical work stages and phases over time.
The CBS is an optional cost hierarchy, used only in the Project Budgeting and Forecasting module, that focuses on controlling costs and revenues.
Components
The WBS consists of operational elements such as the project, sub-projects, activities, milestone activities and tasks. Activities collect information such as real-time progress, time spent, material requirements and actual dates.
The CBS consists of high-level financial categories such as material, labour, sub-contract, plant and expenses, or more detailed breakdowns of them. For example, material can be broken down into valves, concrete and cable, and labour into mechanical and electrical.
Time and operational planning
The WBS is directly integrated with IFS’s built-in planning and scheduling capabilities: Gantt chart, critical path management, activity durations, dependencies and constraints. It triggers operational, commercial and procurement activities.
The CBS contains no scheduling or operational calendar planning; its focus is entirely on analysing and budgeting financial data.
Financial integration and accounting
The WBS collects actual and committed costs and revenues at the level of operational activities: time reports, purchase orders, sub-contract packages and the like.
Cost elements in the CBS, on the other hand, are usually linked to a separate cost element code part in the General Ledger; posting rules are used so that costs flow to the correct cost elements. Using the CBS provides a consistent cost coding structure across all projects.
Flexibility and budgeting
In budgeting and forecasting, users can work with the CBS only, the WBS only, or a combination of both. For example, by combining a WBS representing the project’s phases with a CBS providing detailed cost items, detailed cost budgets can be built for each phase of the project.
In short
The WBS tells you how the work is progressing; the CBS tells you where the money is going. One is the language of operations, the other the language of finance; teams that want to see the project through both lenses use them together.