The CPI (cost performance index) fields show the ratio of budgeted (or baseline) costs of work performed to actual costs of work performed, up to the project status date or today's date. The timephased version of this field shows values distributed over time.
There are two categories of CPI fields.
Data Type Percentage/Number
CPI (task field)
Entry Type Calculated
How Calculated CPI is the ratio of BCWP (budgeted cost of work performed) to ACWP (actual cost of work performed):
CPI = BCWP / ACWP
Best Uses Add the CPI field to a task view to see the ratio of budgeted to actual costs. This value indicates whether you are over or under budget as of the status date.
Example You expected that after two days, 50 percent of a four-day task would cost $60, the BCWP. This task actually incurs a total cost of $70 for the first two days. The task's CPI is about .85, or 85 percent.
CPI (task-timephased field)
Entry Type Calculated
How Calculated CPI is the ratio of BCWP (budgeted cost of work performed) to ACWP (actual cost of work performed):
CPI = BCWP / ACWP
Best Uses Add the CPI field to the timephased portion of the Task Usage view to see the ratio of budgeted to actual costs. This indicates whether you are over or under budget as of the status date.
Example You expected that after two days, 50% of a four-day task would cost $60, the BCWP. This task actually incurs a total cost of $70 for the first two days. The task's CPI is about .85, or 85 percent for both days.