Accreditation, ISO, EFQLM and visitatie are, in essence, control mechanisms in health care systems. An analysis is provided of the way the four models have been adopted and adapted in European health care systems over the past decade. After a short discussion of the major reforms in the European health care systems in the direction of regulated markets, deregulation and decentralization, the features of the four models are highlighted and it is explained how each of them can help to fill the 'accountability gap' between health care providers on the one hand and patients, financiers and governments on the other. The quality system perspective of ISO, the quality management development perspective of EFQM, the health care organization perspective of accreditation and the professional perspective of visitatie can each be appropriate given the balance of power between parties in the health care system and the focus and scope of accountability. Although a general convergence between the four models can be observed, actual convergence will depend on their adoption in specific health system contexts. Potential pitfalls for further convergence are the differences in distribution of responsibilities for quality of care among the various European countries, the drift away from clinical decision making, bureaucratic tendencies and too much focus on efficiency and patient empowerment compared with attention to medical effectiveness.