Although measurement is widely misused in education, it is indispensable in addressing the problems of injustice in global educational opportunity. Considering how the case can be made for legitimate use of measurement in normative analysis and argument, we explore ways in which metrics have featured in the formulation of theories of justice, with particular attention to resourcist and capabilities approaches. We then consider three means of addressing global inequality and defend a reconstruction of the public sphere in which objective measures (...) of justice, deliberatively constructed, could supersede prevalent assumptions about measurement. (shrink)