The use of intraservice work per unit of time (IWPUT) and the building block method (BBM) for the calculation of surgical work

Ann Surg. 2005 Jun;241(6):929-38; discussion 938-40. doi: 10.1097/01.sla.0000165201.06970.0e.


Objective: We will review the contribution to the Medicare Fee Schedule (MFS) by the techniques of intensity of work per unit of time (IWPUT), the building block methodology (BBM), and the work accomplished by the American College of Surgeons General Surgery Coding & Reimbursement Committee (GSCRC) in using IWPUT/BBM to detect undervalued surgical procedures and recommend payment increases.

Summary background data: The MFS has had a major impact on surgeons' income since its introduction in 1992 by the Centers for Medicare and Medicaid (CMS) and additionally has been adopted for use by many commercial insurers. A major component of MFS is physician work, measured as the relative value of work (RVW), which has 2 components: time and intensity. These components are incorporated by: RVW = time x intensity.

Methods: This work formula can be rearranged to give the IWPUT, which has become a powerful tool to calculate the amount of RVW performed by physicians. Most procedures are valued by the total RVW in the global surgical package, which includes pre-, intra-, and postoperative care for a time after surgery. Summing these perioperative components into RVW is called the building block methodology (BBM).

Results: Using these techniques, the GSCRC increased the values for 314 surgery procedures during a recent CMS 5-year review, resulting in an increase to general surgeons of roughly 76 million dollars annually.

Conclusions: The use of IWPUT/BBM has been instrumental to correct payment for undervalued surgical procedures. They are powerful methods to measure RVW across specialties and to solve reimbursement, compensation, and practice management problems facing surgeons.

MeSH terms

  • Centers for Medicare and Medicaid Services, U.S.
  • Fee Schedules*
  • General Surgery / economics*
  • Humans
  • Medicare Part B / economics*
  • Physicians / economics
  • Reimbursement Mechanisms
  • Relative Value Scales*
  • United States