Paying health care providers performance-based incentive payments is one form of results-based financing (RBF). Verifying that providers have reached set performance thresholds is a crucial part of RBF program implementation and key to maintaining the transparency, fairness, and viability of the programs. Since 2004, the United Kingdom's National Health Service (NHS) has been implementing one of the largest RBF initiatives worldwide, the Quality and Outcomes Framework (QOF). The QOF provides incentive payments for primary care providers to improve quality of care and patient experience. Its verification process is well developed and relies on a highly sophisticated clinical information system as the foundation for performance data.This case study describes the verification process of achievement rates under the QOF and identifies lessons learned that applicable to other RBF programs. The case study is part of a broader analysis, which includes multiple country case examples, and aims to expand knowledge about verification and practices to address the immediate design and implementation challenges of RBF programs.