Singer uses data from Michigan covering every public school in the state during the 2020–21 school year. Schools were required to report their current learning modality (fully in-person, fully online, or a mix/option of the two) to the state every month. Singer created a measure of remote learning duration to which more than 992,000 students were exposed in 2020–21 and tracked their attendance from the 2017–18 through the 2023–24 school years—a total of more than 5,100,000 observations. He then tested the differential impact of remote learning exposure via both difference-in-differences and instrumental variable analyses. Neither set of findings is causal because exposure to remote learning was not random (and was often an affirmative parental choice ), but they correlate strongly with each other.
And what of academic outcomes impacted by Covid-era instructional modality changes? A pair of researchers from the University of Western Ontario examine the ways in which math course-taking among high schoolers in Massachusetts changed in 2020–21, including the extent of exposure to remote learning.