The Cost Performance Index (CPI) is a crucial metric in project management, particularly within the realm of cost control. According to the Association for the Advancement of Cost Engineering (AACE) International, the CPI is calculated as:
CPI = BCWP / ACWP
Where:
BCWP (Budgeted Cost of Work Performed): Also known as Earned Value (EV), BCWP represents the budgeted cost for the work that has actually been completed by a specific point in time.
ACWP (Actual Cost of Work Performed): This is the actual cost incurred for the work completed by that same point in time.
The CPI is an index that measures the cost efficiency of budgeted resources for a project. A CPI of 1.0 indicates that the project is on budget, as the actual cost matches the earned value. A CPI greater than 1.0 suggests that the project is performing well in terms of cost (i.e., it is under budget), while a CPI less than 1.0 indicates that the project is over budget.
This metric is vital in cost estimating and control, as it provides project managers with a quantifiable indicator of cost performance, helping them make informed decisions to maintain or correct the project's financial trajectory.