Four Inputs to Project Cost Budgeting

You will want to enter the cost budgeting phase of a project well-equipped. To do this, you will need to know what the inputs to cost budgeting are, and you should understand their importance to the budgeting process.

During cost budgeting, a number of project elements come together to form the project's cost baseline. The following four inputs are used in the cost budgeting process.

1. The project's work breakdown structure (WBS)
The project's work breakdown structure is important in cost budgeting because it organizes all project activities into work packages. Cost budgeting involves assigning a budget, or cost account, to each work package.

Can you imagine trying to assign budgets to project elements if the work was not organized in some way? Without reference to the WBS, vital costs may be overlooked. Any omissions would cause variances later on between planned and actual costs, and cost performance may be reported as "poor."

Part of creating the work breakdown structure is assigning accounting codes to project tasks and activities based on the organization's chart of accounts. Budgeting is simplified when the cost accounts are integrated in this way.

2. The cost estimates for the work
You have made predictions about the costs of the resources required to complete your project's activities. These cost estimates are another important input to cost budgeting.

The budget for each work package is based on the estimates you have prepared. For budgeting purposes, you should be using budget or control estimates with a range of 15 percent or better. The budgeting process may increase an estimate's range by adding an appropriate allowance or contingency to cover the risk of overruns.

3. The project schedule
The third input to cost budgeting is the project schedule. In fact, it is the application of the schedule to the project budget that produces your main tool for cost control: the project's cost baseline.

Once budgets have been assigned to work packages, use the schedule to distribute the predicted costs over time. The project schedule includes the expected start and finish dates for each activity to which costs will be allocated. This information is important to the cost budgeting process because allocated funds must be assigned to the time period in which the costs will be incurred.

As you develop the control budget for your project, you'll find that a bar-chart diagram can be useful. Use it to measure the total costs that fall within each week for planning or comparative purposes. You can easily measure the cumulative costs as the project progresses.

Time-phasing the budget in this way provides the project's cost baseline. Information about cumulative costs over time is also used to determine the project's "burn rate"—that is, the rate at which funds are expended.

4. The risk management plan
Finally, the risk management plan is an important input to cost budgeting. It outlines strategies for dealing with potential risks that could cause project cost overruns. It also can include cost contingencies that are based on the reliability of your cost estimates. You will build contingencies into the budget to compensate for potential cost overruns.

An accurate and appropriate budget is one of a project manager's greatest assets when it comes to cost management. Understanding the inputs to cost budgeting will help you to create such a budget.