The increasing complexity and variation in ART laboratory and clinical practice, together with a recognition of the importance of patient-centered outcomes, makes ART registries a central resource for informing patients, regulators and governments about the performance of ART treatment. The sequential nature of ART treatment gives rise to a multitude of possible numerators and denominators for measuring treatment outcomes. Which combination of these is the most appropriate and important depends on the stakeholder perspective and the purpose of the measure. ART registries are used in a number of countries to measure ART performance, particularly for reporting at a fertility clinic level. While health data transparency generally leads to better decision making, the process of measurement itself has the potential to both positively and negatively alter the behavior of clinics and clinicians. Finally, personalized patient predictor tools developed using large registry datasets are becoming common and are likely to become an important tool to assist clinicians in counselling patients about their individual chances of ART success.