Use of Percent of Constraint Removal to Measure the Make Ready Process

Project process controls have traditionally occurred after-the-fact, and have focused exclusively on finding discrepancies and measuring results after a specific period of time. The Last Planner® System (LPS) is a production planning and control tool focused on the make-ready and shielding processes for improving workflow reliability. In the LPS, percent plan complete (PPC) has been used as a measurement of the shielding process. However, the system lacks a measurement for the makeready process. This paper proposes a new measurement for the make-ready process called percentage of constraint removal (PCR). This new measurement of constraint removal would be an efficient and flexible means to measure the make-ready process. This measurement provides 1) a leading indicator for work production performance, 2) a performance measurement for the make-ready process, and 3) how appropriately to size the look-ahead window. This paper presents three case studies of heavy construction projects where both performance measurements, PCR and PPC, were applied and investigated. How PCR and PPC are correlated with progress performance was also studied.