WBS and OBS
- 1. WBS AND OBS Abdul Qadeer Bilal
- 2. WBS And OBS The Work Breakdown Structure (WBS) is a tool that defines a project and groups the project’s discrete work elements in a way that helps organize and define the total work scope of the project. A WBS element may be a product, data, a service, or any combination. WBS also provides the necessary framework for detailed cost estimating and control along with providing guidance for schedule development and control. Additionally the WBS is a each descending level of the WBS represents an increased level of detailed definition of the project work. Remember the WBS defines a project and groups the project elements for managing a project. An organizational chart describes the project team that will accomplish the project. Not all projects have a WBS, and it is true that some of these projects have been successful. So why is a WBS needed? We have already looked at a few reasons, but in review, the WBS: – Provides a framework for organizing and managing the approved project scope – Helps ensure you have defined all the work that makes up the project – Provides a framework for planning and controlling cost and schedule information – It’s better to be deliberate about planning than rely on luck! Additionally, when you work for a company or organization that has many projects being performed simultaneously, each of the projects is competing for the limited resources available. The WBS enables you to review project details and distinguish one project’s needs from others within the company or organization. Why is distinguishing one project from another important? It enables you to identify resource requirements and allocate resources more effectively. Example: The ACME Housing Corporation, which you own, has been contracted to build its first house. You want to be able to manage your projects effectively and efficiently, so you charge your project managers to develop an appropriate WBS. You decide to manage the project by the individual tasks necessary to complete the house. You hope that this is the first of many houses that ACME will build, so you start the WBS with ACME in the highest position, or Level 1. Accordingly, Level 1 is given a WBS code of 1. You assign the WBS code of 1 to the highest level because all future projects (houses) will be summarized at Level 1. NOTE: For ease of explanation, our example will assume the following: • Design is complete • All permits issued • All Material ordered • Inspection happens
- 3. With Level 1 established, you can begin to complete the WBS. But what should the next level be? The logical next level for ACME is the project level. Level 2 is the level for each individual project, or house, that ACME undertakes. As the chart shows below, Level 2 is identified at the project level: House. Appropriately, the code for Level 2 corresponds to Level 1. In this case, the code is 1.1. Now the WBS for the housing project is complete, right? Actually, no, the WBS is not complete. At this point you determine that you want to divide the work into the major elements needed to build a house. You choose to divide Level 3 into six elements: concrete, framing, plumbing, electrical, interior and roofing. You realize that these are both major deliverables and milestones for managing the project. They also enable you to get to your goal of managing the project by task. Notice the WBS codes at level 3. Each is unique to the project and starts with the WBS code from the level above (1Æ1.1Æ1.1.1). Now lets look and see if another level is needed. The ACME WBS is taking shape, but it does not quite define the project at a level that shows needed tasks for completion. To do this, one more level needs to be included. Level 4 of the WBS will enable us to manage the project as desired. All of our contractors fit into specific elements at level 4, and so do all specific departments. As with the previous Levels, note the WBS codes that have been assigned to the tasks and their relationship to the previous Level.
- 4. What do you think? Is the WBS complete? Does it enable the manager to manage at the task level? After a review to make sure that only approved scope is included, our WBS is complete. It does include the necessary components to manage the project by task. Now that our WBS is developed, the appropriate resources and responsibilities need to be assigned. The first step in doing this is developing the Organizational Breakdown Structure (OBS) for the project. The OBS indicates the organizational relationships and is used as the framework for assigning work responsibilities. Below is an example of the OBS for the ACME house building project. The OBS is structured by Responsible Department and then by Performing Department at the lowest level. This
- 5. Performing Department level is where the responsibility and resource needed to accomplish the project will be assigned. With the relationships and responsibilities defined, the second and final step is to merge the WBS and OBS. Merging the WBS and OBS, the project manager creates a Responsibility Assignment Matrix (RAM). The RAM displays the lowest level of both the WBS and the OBS. The integration identifies specific responsibility for Responsibility Assignment Matrix CONCRETE PERF DEPT 6010 M. Manning MASONRY PERF DEPT 6020 T. Greams TEST PERF DEPT 6030 K. Neumann CIVIL RESP DEPT R. Kelly CARPENTRY PERF DEPT 5010 R. Sites ROOFING PERF DEPT 5020 Y. Taylor DRYWALL PERF DEPT 5030 D. Smith STRUCTURAL RESP DEPT P. Tate PERF DEPT 4010 S. Johnson HOOKUP/TIE-IN PERF DEPT 4020 P. Ottis ELECTICAL RESP DEPT J. Sims WATER/SEWER PERF DEPT 3010 K. Wells GAS PERF DEPT 3020 R. Oriely PLUMBING RESP DEPT R. Lee PROJECT OFFICE RESP DEPT B. Smithers WIRING CONCRETE PERF DEPT 6010 M. Manning MASONRY PERF DEPT 6020 T. Greams TEST PERF DEPT 6030 K. Neumann CIVIL RESP DEPT R. Kelly CARPENTRY PERF DEPT 5010 R. Sites ROOFING PERF DEPT 5020 Y. Taylor DRYWALL PERF DEPT 5030 D. Smith STRUCTURAL RESP DEPT P. Tate PERF DEPT 4010 S. Johnson HOOKUP/TIE-IN PERF DEPT 4020 P. Ottis ELECTICAL RESP DEPT J. Sims WATER/SEWER PERF DEPT 3010 K. Wells GAS PERF DEPT 3020 R. Oriely PLUMBING RESP DEPT R. Lee PROJECT OFFICE RESP DEPT B. Smithers WIRING specific project tasks.
- 6. Below is part of the RAM for the ACME housing project. – The lowest level of the WBS appears across the top – The lowest level of the OBS appears on the vertical axis An “X” appears at the intersection of the WBS task and OBS personnel. The “X” defines the specific performing department (from the OBS) assigned to complete a task (from the WBS).
- 7. To better understand the RAM, consider the ACME housing project. The OBS specifies Mr. Sites and the carpentry department as responsible for framing the exterior walls. Therefore, in the RAM, an X appears at the cross-section between the task, framing the exterior walls, and the responsible party, Mr. Sites. Additionally, Mr. Sites is also responsible for framing the interior walls and installing the roofing trusses.