The purpose of this technical appendix is to share more detailed results and to describe more fully the sample and methods used in the research included in the brief, "Student achievement in 2021-22: Cause for hope and continued urgency." The authors investigated two main research questions in this brief: (1) How do achievement gains across the 2021-22 school year compare to pre-pandemic trends? Are there any initial signs of rebounding or recovery?; and (2) How does student achievement in spring 2022 compare to pre-pandemic levels? In addition to these two primary research questions, the authors also investigated one supplementary research question regarding whether achievement has become more distributed over the pandemic. [For "Student Achievement in 2021-2022: Cause for Hope and Continued Urgency. Collaborative for Student Growth. Brief," see ED623610.]