The OPERA Framework principles to take into account when monitoring ESC rights fulfillment and offers practical guidance on which tools and techniques might be employed to evaluate them. These range from simple descriptive statistics that summarize data to more complex fiscal policy and budget analysis that assess the availability and allocation of resources. By making explicit this crucial link between the various human rights standards and principles that underpin the obligation to fulfill and the different assessment methods available to monitor them, the framework enables a systematic approach to building evidence of failures to fulfill ESC rights. This framework has been developed by the Center for Economic and Social Rights (CESR), an international non-governmental organization, as part of its work to promote greater accountability for breaches of this duty, which underlie many of the most widespread and pervasive deprivations of ESC rights. By providing an overarching framework to integrate multiple tools and methods, the OPERA framework enables advocates and activists to build up a well-evidenced argument about a state’s compliance with its obligation to fulfill ESC rights. This can be very powerful for advocacy, whether focused on securing remedies for current violations or on advancing reforms for preventing them in the future. On the one hand, providing quantitative, cross-disciplinary evidence demonstrating the link between poor development outcomes and breaches of the obligation to fulfill economic and social rights can prompt ‘decision-makers’ to be more responsive to, or at least less dismissive of, human rights arguments. At the same time, supporting rights-holders to expose and articulate the injustices they face using robust, credible methods anchored in the human rights framework can help give their demands for justice renewed force. iv