Multilevel models are widely used in education and social science research. However, the effects of omitting levels of the hierarchy on the variance decomposition and the clustering effects have not been well documented. This paper discusses how omitting one level in three-level models affects...

The COVID-19 pandemic caused significant disruption in schooling in the U.S., and student test scores showed dramatic declines by the end of the 2020-21 school year. We use state test score data to analyze patterns of test score recovery over the 2021-22 school year. On average, we find that 20%...