This paper draws on recent research in Europe and England to discuss the politics of accountability. It is suggested that, as policies in education are increasingly focused on delivering technical-managerial accountability, that is accountability understood as evidenced in international, national, institutional and individual comparative measures of performance, so the shifting power relations of system redesign supported by data use are concealed and suppressed. System redesign is promoted by 'networked' governance and the de-centred state, in institutional 'freedom' from bureaucracy, in the de-professionalisation of public sector workers, in the proliferation of managers, in the redefinition of citizens as consumers. The implications of such reforms for politics are profound, as political legitimacy is a fundamental precondition for the sustainability of the welfare state and welfare state organizations are dependent on active political processes of producing legitimacy and political accountability.