Open Plan Cost Calculations
Cost calculations are among the most feature-rich aspects of Open Plan. Using cost calculations, you can calculate current values for both budget and actual costs, compare these values to baseline budget and actual costs, and calculate earned value.
The following discussion is provided to give you a general understanding of how Open Plan calculates these values.
In Open Plan, all costs come from the cost of the resources assigned to a project. This means that unless a project uses resources, you cannot use Open Plan to calculate or display costs.
Costs calculations take place at all levels within a project.
Cost Calculations at the Resource Level
The manner in which resources are assigned has ramifications for the way the resource cost is calculated. In Open Plan, resources can be assigned in either of the following two ways:
- Total: When resources are assigned using any of the available spread curves, Open Plan interprets the value as a specified total of resource units required by an activity regardless of the activity duration. Resources that are assigned in this way can be multiplied by a unit rate to yield a currency value.
- Level: When resources are assigned without using a spread curve, Open Plan interprets the value as a specified level of resource units required by the activity for each time unit. Resources that are assigned in this way must first be multiplied by a duration before you can apply a rate to yield a currency value. The duration used in this calculation can be either the resource duration (called a period) or the duration of the activity to which the resource is assigned. If it is entered, Open Plan uses the resource period in preference to the activity duration.
Depending on how the resource is defined in the Resource Details dialog box, the rate used in calculating the resource cost can be either a flat rate or one that can escalate over time.
Open Plan recognizes four types of resource category:
- Labor
- Material
- Other Direct Costs
- Subcontract
The category type for each resource is defined in the Resource Details dialog box. Each category is rolled up to fields on the activity by category.
For labor resources, Open Plan rolls up the budget, earned value, scheduled value, actual quantities, and remaining quantities to the activity and subproject levels of the project provided that:
- Budget is stored in the BAC_QTY field of the activity.
- Earned value is stored in the BCWP_QTY field of the activity.
- Scheduled value is stored in the BCWS_QTY field of the activity.
- Actual quantities are stored in the ACWP_QTY field of the activity.
- Remaining quantities are stored in the ETC_QTY field of the activity.
For all resource classes, the resource definition table contains a field called the Roll Cost flag. The value of this field is set to True by default. If you change this value to False for a specific resource, Open Plan does not use that resource during cost calculations. To set the value to False, clear the Consider in Cost Calculations option on the General tab of the Resource Details dialog box for that resource.
Cost Calculations at the Activity Level
Open Plan stores the rolled-up values of the budget and actual cost of resources in the activities to which the resources are assigned.
In addition, if a baseline is applied to the project, the cost calculations process can also calculate the budgeted cost of the work scheduled for each activity. Open Plan performs this calculation by looking at what baseline budget value should have been accomplished by the current Time Now date.
Open Plan uses the Project Measurement Baseline (PMB) for this calculation if it exists. If the PMB does not exist, Open Plan uses the currently selected baseline, or, in the case of multiple baselines, the first selected baseline.
Activities also take advantage of many calculated fields to derive values from those that are rolled up.
Cost Calculations at the Subproject Level
Subprojects may have their own resources assigned to them. Typically, resources that are assigned at the subproject level are those that work as long as the subproject takes. These are known as Level of Effort resources. The cost calculations that are performed at the subproject level are the same as those performed at the activity level.
In addition, the Include Child Activity Values in Subproject Costs option in the Cost Calculations dialog box has ramifications for cost calculations:
- If this option is selected, Open Plan rolls up budget and actual values from child activities to their parent subprojects.
- If this option is cleared, a
subproject calculates budget values from its own resources but not from child
activities.
If you report on a project using grouped views, you may wish to turn this feature off in order to avoid double counting the activity cost by including it in both the activity and its parent subproject.
The subproject physical percent complete (PPC) is calculated by summing the activity BCWP values of the activity and dividing by the summed baseline BAC cost fields for all categories:
Subproject PPC = Sum(BCWP_CST)
Cost Calculations at the Project Level
Projects inherit their rolled up physical percent complete, budget costs, and actual costs from these values in their activities.
- Activity
- Subproject
- Project