Work Breakdown Structures

Purpose The WBS shows different levels within the product hierarchy. For Government program managers levels 1-3 are of prime importance Level One – Overall System Level Two – Major Element (Segment) Level Three – Subordinate Components (Prime Items)

Levels Level One – Overall System Level 1 is the entire defense materiel item; for example, an electronic system. An "electronic system“ might be a command and control system, a radar system, a communications system, an information system, a sensor system, a navigation or guidance system, or an electronic warfare system. Level 1 is usually directly identified as a program or a sub-element of a program.

Levels Level Two – Major Element (Segment) Level 2 elements are the major elements of the defense materiel item; for example, a fire control system or an automatic flight control system. These prime mission products include all hardware and software elements, aggregations of system level services (like system test and evaluation, or systems engineering and program management), and data.

Levels Level Three – Subordinate Components (Prime Items) Level 3 elements are elements subordinate to level 2 major elements. For example, a radar data processor, a signal processor, an antenna, a type of service (like development test and evaluation, contractor technical support, or training services), or a type of data (like technical publications) would be typical level 3 elements for an electronic system. Lower levels follow the same process.

Aircraft System Air Frame Engine Navigation L E V E L O N E L E V E L T W O L E V E L T H R E E Training Support Equipment Air Vehicle

Benefits Separates a defense materiel item into its component parts, making the relationships of the parts clear and the relationship of the tasks to be completed -- to each other and to the end product -- clear. Significantly affects planning and the assignment of management and technical responsibilities. Assists in tracking the status of engineering efforts, resource allocations, cost estimates, expenditures, and cost and technical performance. Helps ensure that contractors are not unnecessarily constrained in meeting item requirements.

Challenges The primary challenge is to develop a Work Breakdown Structure which defines the logical relationship between all the elements of the program and its natural extension with the contract. If the government considers elements of the program to be high cost or high risk, the system may be defined to a lower level of the WBS. This is reasonable as long as the product-oriented logical extension is maintained. A second challenge is to balance the program definition aspects of the WBS with its data-generating aspects. However, the primary purpose of the Work Breakdown Structure is to define the program's structure, and the need for data should not distort or hinder the program definition.

WBS Glossary Lists and defines WBS elements –Initially based on generic definitions –Refined as more information is acquired Definition –Resources –Reference to designs, drawings, technical documents –Point of Contact –Any other relevant information

Pitfalls Do not include non-essential elements Try to stick to products Do not use org chart as WBS Use accurate (not generic) names Include software if appropriate

WBS Summary The WBS serves as the coordinating document for the program. The WBS guides –Resource allocation –Resource expenditure –Work progress Keeps program status constantly visible in order to monitor changes

Gantt Charts An Intro

Gantt Chart Display in a single “picture,” the flow of tasks, predecessors and successors that describe the execution of the project. A visual representation of the sequencing and duration of activities on a given project

Gantt Chart Predecessor– a task that must be completed immediately before another Successor– a task that must wait for this task to be completed

Gantt Chart Advantages Easy to read Good overview Clear indication of status Able to track progress What-if analysis Can show many details –Budget –resources

Gantt Chart Time across top Activity represented by a bar –Filled/non-filled –Triangles up and down Lines for predecessors (some) Resource requirements

Time Estimates Historical Data Same project Historical Data Similar project Expert Opinion Known delays Unknown delays (margin) Resource availability Management support Simulation

Gantt Chart Tasks Identify tasks Identify dependencies Identify resources needed Estimate durations –Units of measure –Available margin Determine task 1 Draft chart Refine

Draft Chart Initial Task Entry-- no predecessor Lower tasks-- no predecessor Identify predecessor tasks that depend on shortest “np” tasks Repeat Draw dependency lines (only latest) Enter resource requirements

Gantt Chart Disadvantages Can get very large Tedious to update Precedence sometimes difficult to display Resources kind of added later Priorities not shown

Gantt Charts and Computers Lots of software –Microsoft Project Easier to create and update –Must check carefully Hard to show on one screen –Must scroll Precedence must be checked carefully