This is the technical index for the research brief "Education's Long COVID: 2022-23 Achievement Data Reveal Stalled Progress toward Pandemic Recovery." Using data from 6.7 million U.S. public school students currently in grades 3-8, the study examined academic gains in the 2022-23 school year relative to pre-pandemic years. It also tracked the gap in achievement between the COVID year student group compared to their pre-pandemic peers. Key findings show that while learning did continue, progress toward academic recovery stalled in the 2022-2023 school year. Significant achievement gaps persist at the end of the 2022-2023 school year, and the average student will need the equivalent of 4.1 additional months of schooling to catch up in reading and 4.5 months in math. [For the full report, see ED630208.]