The work breakdown structure (WBS) is the key to successful projects. The WBS produced a list of the individual pieces of work that must be done to complete a project. These are the building blocks of the project. Each of these represents a portion of the work of the project. Each must be the responsibility of one and only one person on the project team. The person responsible for an individual piece of work is similar to the project manager and is responsible for all that happens in the project regarding that piece of work. That person is responsible for scheduling, cost estimating, time estimating, and of course seeing that the work gets done. Like the project manager, the person responsible may not be required to do all the work. He or she is, however, responsible for seeing that it gets done.
In order to determine the project cost accurately enough to be considered the project cost baseline, a bottom-up estimate must be made. This estimate must have an accuracy of — 5 percent to +10 percent. This type of estimate will be produced by estimating the cost of each item at the bottom level of the WBS and then summarizing or rolling up the data to the project level.
Bottom-up estimates are inherently more accurate because they are a sum of individual elements. Each of the individual elements has a possibility of being over or under the actual cost that will occur. When they are added together, some of the overestimates will cancel out some of the underestimates.
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What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.