One of the most exciting products generated and refined through the Early Learning Network studies is a web-based classroom assessment tool known as OLOS -- the Optimizing Learning Opportunities for Students Observation System. The OLOS tool focuses on improving student outcomes by providing teachers with real-time data to support individualized assessment and instruction. The network's collective findings associated with the OLOS tool are summarized in this report, which may help inform practice and policy decisions that support equitable and effective learning opportunities for children.