In the United States, students have historically taken large-scale assessments for many different purposes. One purpose that is shared with many other countries is a desire to monitor aggregate trends in educational attainment in core subject domains such as literacy, mathematics, and science. In this commentary, the author examines testing, assessment, and educational accountability in the United States over the 14-year period from 2002 to 2016. He argues that the need for large-scale assessment designs directly informed by theories of learning have increased over this period. The reason for this is a shift in the purpose and use of educational assessments. In the past, assessments in the U.S. had been used primarily to monitor what students have learned; however in the present there is a greater desire to use them to monitor and evaluate what students are learning. This shift in emphasis, the author argues, has opened a space for learning theory to play a bigger role in not only assessment design, but in psychometric theory and practice. [This article is a commentary on Jo-Anne Baird, et al.'s "Assessment and Learning: Fields Apart" (EJ1149539).]