Adding Organizational Breakdown Structure and Resource Assignment Matrix to the Work Breakdown Structure

In fact, the WBS is not one entity, but actually three:

■ The WBS itself is the hierarchical structure of deliverables (nouns), and when applying the WBS in the context of contractor-subcontractor, the prime WBS is often referred to as the project or program WBS (PWBS) and the subcontractor's WBS is referred to as the contract or contractor WBS (CWBS).

■ A structure similar to the WBS can be made for the organizations that participate in the project. Such a structure is called the organizational breakdown structure (OBS).

■ The OBS and the WBS are cross-referenced with the resource assignment matrix (RAM).

Figure 3-4 shows the three component parts working together.

V/wk 0 rea kdown SlrjcUrc. WB5

Ce Iverafcte

De i-dtan o

Cc i^C itJlC

Cirpfini7alim Breakdown Hesourae Assignnftnl Walnx,

Sifucture. OGS RAM

Figure 3-4: WBS Components.

The RAM is where the analytical aspects of the WBS come into play. At each node of the RAM where there is an intersection of the OBS and WBS, the resource commitment of the organizations is allocated to the WBS. From the RAM, the resources can be added vertically into the WBS hierarchy and horizontally into the OBS hierarchy. Such an addition is shown in Figure 3-5. Note that the following equation holds:

(All WBS resources) =

(All OBS resources) = Project resources

Deliverable a = 15 hours, \$750 Deliverable b = 35 hours, ¿1,400 Deliverable c = 10 hours, S500 Project = 60 hours, \$2,650

Deliverable a = 15 hours, \$750 Deliverable b = 35 hours, ¿1,400 Deliverable c = 10 hours, S500 Project = 60 hours, \$2,650

 Deliverable 1 Deliverable a. | b || c 3 /J ► 4 \ I 4 ¥ t; e TI i r i r

IF = 10 hours, S500 IF "B" = 25 hours, \$300 IF "C* = 15 hours. 3750 IF "D" = 10 hours. «600

Department 1 = 25 hours, J 1.350 Department 2 = 25 hours, SSM Department 3=10 bouns, \$500 Organization = 60 hours, \$2,650 Figure 3-5: Adding Up the RAM.