Specialty board certification is very important to both physicians and patients. Although certification does not imply or assess competence per se, it does positively correlate with other quality measures. The assessment of knowledge is a critical part of certification by the American Board of Surgery (ABS) because knowledge is fundamental to understanding, judgment, and clinical decision making in surgery. The relationship between knowledge and performance is underscored by advances in the field of cognitive psychology. Given the importance of certification, ABS examination development and scoring processes use widely accepted psychometric principles to ensure a high degree of validity and reliability. The ABS also closely monitors the examinations to maintain the integrity of the examination process. This article details some processes the ABS uses to achieve these ends.