I found this study through a retweet by Dirk Van Damme of this thread (read further after the thread):
This study may seem surprising to some but less to me as I saw similar things happening closer to home, and while I couldn’t measure the effect, I do recognize the positive outcome. I expect many discussions about everything countries have done right and/or wrong during the pandemic when international comparisons such as PIRLS (this month) and PISA will be published (by the end of this year). Do know it’s always more complicated and this kind of studies only allow for correlation, not causal relationships.
From experience to meaning... 