The PMI process of control costs is in the monitoring and controlling process group in the cost management knowledge area. It involves identifying significant deviations from the cost baseline, so corrective action can be taken when needed.

According to the PMBOK, this activity has the following characteristics:

Inputs Tools and Templates Outputs
project management plan, project funding requirements, work performance data, organizational process assets earned value management, forecasting, to complete performance index (TCPI), performance reviews, project management software, reserve analysis work performance information, cost forecasts, change requests, project management plan updates, project documents updates, organizational process assets updates

Control costs is described in section 7.4 of the PMBOK, 5th edition.

Related: earned value