Budgeted cost of work performed (BCWP) also called earned value (EV), is the budgeted cost of work that has actually been performed in carrying out a scheduled task during a specific time period.
[1] The BCWP is the sum of the budgets for completed work packages and completed portions of open work packages, plus the applicable portion of the budgets for level of effort and apportioned effort.
BCWP is contrasted to Budgeted Cost of Work Scheduled (BCWS) also called Planned Value (PV).
To illustrate the difference between the three terms, assume that a schedule contains a task "Test hardware" estimated to run from 1 January to 10 January and to cost $1000, and that this is a simple effort with no overhead or allocated costs.
The comparison in Earned value management would view this as behind schedule and costing less overall than expected.