Historically the performance of health-care professionals has been evaluated primarily through assessment of content knowledge retained in memory. Yet human performance is influenced by elements that are both intrinsic and extrinsic to the human being. Intrinsic elements consist of cognitive, technical, and behavioral skill sets. Extrinsic elements are described by the field of ergonomics and include cognitive, physical, and organizational domains. Identifying the requisite skills, defining competent performance in each of these skills, determining appropriate forms of competency assessment for each skill, and designing easy-to-use assessment tools are the key steps to achieving objective, comprehensive, and consistent evaluation of performance. Performance assessments that fail to take into account these complexities are incomplete and simplistic at best, and at worst, inaccurate and misleading. Rigorous assessment of human performance in neonatal-perinatal medicine will greatly enhance the delivery of effective, safe, and efficient neonatal care.