The competition's second round was launched in July 2019 . In this new phase of the competition it was the intention to use the best-performing models to perform the most important task of all: to predict new chemical matter that would be active (rather than merely look at the fit of retrospective data). Synthesis and evaluation of these predictions would then serve as model validation in a "real" case. A small, new dataset of activity from recentlysynthesised analogs was kept back to serve as the basis for judging model fitness.