NUMBERING THE WBS

In developing a WBS, logical coding or numbering of the various elements and levels significantly improves the functionality of the WBS in various related applications. The coding can be done by any method, but it is important to be consistent. Most organizations have standard codes. These codes can be used and modified to contain numeric/alpha elements, which will give a unique identification to every work activity and facilitate sorting for special reports. The resulting identification provides a label for scheduling, budgeting, tracking, replanning, assigning, and in general, for communicating across the project. Many of the project management software packages allow you to enter the WBS codes and to use these codes for sorting data and preparing specialized reports.

EVMSs usually require formally established numbering systems for cost data based on an enterprise-wide table of accounts. The accounting system requires that the project number, control account number, and work package number be identical to the WBS number, or to map to it. In addition, the accounting system needs to be able to accumulate direct costs within work packages for labor, material, travel, subcontracts, and other direct costs (ODC) through the EVMS and general ledger into the enterprise financial statements. Activity numbering also relates to WBS numbering, as shown in Figure 2-15. So it is necessary to have a system that is capable of summarizing cost and schedule data from the activity level through the work packages and control accounts by organization and by WBS level.

Some mature organizations use standard WBSs for classes of products in order to be able to gather cost data by key WBS elements across projects. For these organizations, the definition and numbering of the elements at least at the top levels may be specified and controlled. The purpose is to be able to populate and maintain databases of historical data in order to develop cost-estimating relationships (CERs) and for various analyses.

There are many possible numbering systems for the elements of the WBS. The purpose of all numbering systems is to be able to identify the WBS work element readily and to determine where it fits in the overall project hierarchy. WBS elements frequently have similar names, and the numbering system clearly identifies each discrete element.

A decimal numbering system as shown in Figure 2-19 is commonly used.

FIGURE 2-19 Generic Decimal Outline Numbering

The decimal numbering system is precise and thorough, and it can continue to whatever level is necessary. The numbering system shown in Figure 2-20 is for the Garage Project. If there are several projects in an organization, and similar WBS elements in each, a prefix such as GP1 (Garage Project One) could be added to distinguish projects.

FIGURE 2-20 Garage Project Numbering

This numbering would be extended into all the activities in the schedule or network diagram so that every activity would be discretely identified.

This decimal outline numbering matches typical accounting systems numbering, which facilitates cost accounting, cost roll-up, and EVMSs.

Chapter 3 provides an illustration of how software such as Microsoft Project uses the WBS Code Definition feature to provide flexibility in the type of numbering system used.

Other internal systems using the WBS as an organizing framework are as follows:

Action item tracking—Relating action items from meetings and reviews to WBS numbers.

Bills of material—The WBS number may be included in the part number or vice versa.

Change management—Change proposals include WBS numbers.

Correspondence control—In addition to day files and organization files.

Data management.

Drawing numbers—Part of the drawing number includes the WBS number from the Product WBS elements.

Report numbering.

Risk management—Relating specific risks from the risk identification process to the WBS elements.

Subcontract numbering.