On behalf of the National Governors Association (NGA), and with support from the Robert Wood Johnson Foundation (RWJF), the State Health Access Data Assistance Center (SHADAC) has developed this resource, which highlights states that have released data thresholds, sometimes referred to as gating criteria or benchmarks, to guide schools, school districts, and other stakeholders in decisions on full or partial school reopening. The resource outlines common measures upon which thresholds are based and explores how measure definitions and thresholds compare across states, provides examples of how guidance has evolved since the 2020-2021 school year began, and includes information on other resources tracking school COVID-19 status and response. The information presented in this resource draws from SHADAC's review of publicly available information on state websites in late September and early October. States frequently re-assess and revise policy and many states released guidance over the summer months in anticipation of the 2020-2021 school year, which predated the latest guidance from the Centers for Disease Control and Prevention (CDC). These factors suggest adaptations of these policies are likely over time. [This report was prepared by State Health Access Data Assistance Center (SHADAC) on behalf of the National Governors Association (NGA).]