This chapter focuses on innovations in test development that have made it possible to increase the relevance and utility of international large-scale surveys. In response to the rapid evolution of digital technologies, policy makers, educators, and other stakeholders are increasingly interested in better understanding the extent to which student and adult populations possess the skills that are required to succeed in changing times. Experience with the Program for International Student Assessment (PISA) and the Program for the International Assessment of Adult Competencies (PIAAC) is presented, focusing on the development of computer-based items in the legacy constructs of reading, mathematical, and scientific literacy for PISA and literacy and numeracy for PIAAC. Innovative work around these cognitive domains has been driven by three factors: (1) assessment frameworks that have evolved to reflect the growing importance of digital information, (2) platform capabilities that support both interactive environments and new item types that can be used to assess the range of skills required to navigate, critically analyze, and problem solve in complex digital environments, and (3) the implementation of innovative scoring and data capture capabilities. Collaborative efforts among domain experts, psychometricians, test developers, platform specialists, data analysts, and translation specialists, have led to new capabilities that make it possible to enhance the relevance of large-scale international assessments by expanding both the range of skills that can be measured and the means by which those skills are assessed.