Postoperative venous thromboembolism is one of several preventable conditions for which hospitals will not receive additional reimbursement from the Centers for Medicare and Medicaid Services. The AHRQ Patient Safety Indicators (PSIs) are intended for use in screening medical records to identify possible safety events. However, this study found that the PSI for postoperative venous thromboembolism lacks sufficient predictive ability to be used as the sole method for detecting cases.