Monitoring Sustainable Development Goal 4 requires reliable, high quality and cross-nationally comparable data compiled at regular intervals. Launching such a global assessment scheme would be the ideal – but this will take years, perhaps decades. As a second-best alternative, we use a rigorous yet comprehensive methodology which provides globally comparable data for the proportion of students reaching the Minimum Proficiency Level (MPL) in reading and mathematics. Our approach creates indices of comparison between differing assessments where enough countries participate in both. This enables swift and efficient comparison, since no additional instruments or costs incurred in the anchoring process. Based on this methodology, we obtain an international dataset on students reaching the MPL in both primary and secondary schools for more than 160 countries/localities between 1995 and 2015 and for more than 30 Sub-Saharan African countries. We conduct a series of robustness tests and provide confidence intervals for each estimate in order to enhance reliability for our estimates, and we clearly delineate the limitations of the study. To the best of our knowledge, this study provides the largest and most internationally comparable information available for monitoring Sustainable Development Goal 4 for the education sector.