CIES 2018 Presentation, given by Luis Crouch. Given the prominence of learning and quality in the SDGs, much discussion has gone into how to measure in a manner that is reasonably comparable. Some have argued (or feared) that this would necessitate a single, dominant, global assessment. Aside from the political or ethical acceptability of this kind of imposition, one has to wonder how meaningful this could be, psychometrically or pedagogically. The paper will argue that unless one were to increase the cost of assessment tremendously, or make children sit through lengthy assessments or until highly adaptive computerized assessments can be used, a single or a few dominant assessments are an unlikely approach. Instead, a variety of assessments is a more likely solution. These might have better psychometric “resolution” for poorer countries with greater cognitive inequality than the OECD countries, might be closer to the children’s actual levels, and might be psychometrically more reliable if done properly. The ability to make the results comparable or equitable in some sense need not be lost, however, if some sort of universal learning scale is created, so that countries can peg themselves, with reasonable rigorous, to that scale. A global neutral arbiter can “sponsor” the scale and compile country-based reports using it.