WORK BREAKDOWN STRUCTURES.

WBS.
It is a bottom-up estimation tool. It is a hierarchical chart that accounts for the individual parts of a system. This chart can indicate either product hierarchy or process hierarchy.

It identifies the product components and indicates the manner in which the components are interconnected. It describes the fundamental structure of the software, showing how the various software components fit into the overall system.

PRODUCT HIERARCHY.

A Product Work Breakdown Structure.
Software Application

Component A

Component B

Component N

Sub comp: B1

Sub comp: B2

It identifies the work activities and the relationships among those activities.

PROCESS HIERARCHY.

STRUCTURE OF PROCESS BREAKDOWN SYSTEM.
Development Activities

System Engineering

Programming

Maintenance

Detailed Design

Code And Test Unit

CONTD…
It is an essential tool in the project planning process. It is a logical hierarchy that organizes and breaks down the work that needs to be accomplished on a project . It is a way of organizing projects elements into a hierarchy that simplifies the task of budget estimation and control.

THE WBS Contd..
Using the WBS technique, costs are estimated by assigning costs to each individual component in the chart and summing the costs. Both product and process WBS charts are used for cost estimation by some planners.

THE PURPOSES.
It defines and breaks down the work on a project into manageable chunks often called work packages. It tells us what activities or tasks have to be done in order to complete the project. It serves as the foundation for the development of schedules, budgets and resource requirements. It serves as a useful tool for identification of activities and assignment of responsibilities.

ADVANTAGES.
The primary advantage of WBS are in identifying and accounting for various process and product factors, and in making explicit exactly which costs are included in the estimate. It is good for planning and control. It is used in cost accounting and reporting. It helps to determine just exactly what costs are being estimated.