This report highlights key reasons for the need for large-scale learner assessments and emphasizes the importance of measuring learning outcomes in a valid, reliable and recurring manner. These guidelines showcase best practices for the design, implementation and analysis of state-led large-scale assessments. They are supplemented with case studies of assessments conducted in India and around the globe, to bring forward how decision-makers have designed outcomes-focused solutions in various contexts. This report aims to support a culture of evidence in building strong learning outcomes in states. With in-depth explanations of the steps involved in assessment design, implementation, analysis and result dissemination, this document can act as a companion to state decision-makers who are encouraging large-scale assessment in their constituencies.