Progress testing is gaining ground rapidly after having been used almost exclusively in Maastricht and Kansas City. This increased popularity is understandable considering the intuitive appeal longitudinal testing has as a way to predict future competence and performance. Yet there are also important practicalities. Progress testing is longitudinal assessment in that it is based on subsequent equivalent, yet different, tests. The results of these are combined to determine the growth of functional medical knowledge for each student, enabling more reliable and valid decision making about promotion to a next study phase. The longitudinal integrated assessment approach has a demonstrable positive effect on student learning behaviour by discouraging binge learning. Furthermore, it leads to more reliable decisions as well as good predictive validity for future competence or retention of knowledge. Also, because of its integration and independence of local curricula, it can be used in a multi-centre collaborative production and administration framework, reducing costs, increasing efficiency and allowing for constant benchmarking. Practicalities include the relative unfamiliarity of faculty with the concept, the fact that remediation for students with a series of poor results is time consuming, the need to embed the instrument carefully into the existing assessment programme and the importance of equating subsequent tests to minimize test-to-test variability in difficulty. Where it has been implemented—collaboratively—progress testing has led to satisfaction, provided the practicalities are heeded well.