By Chenchen Shi, Johns Hopkins University

Almost three years since the COVID-19 pandemic, there is a growing number of studies examining the learning loss of school-aged children during the pandemic. The first meta-analysis of global learning loss has been published in Nature Human Behavior, and reviews the existing evidence on the extent to which learning progress has slowed down since the onset of the pandemic, and how it varies across different groups of students, subject domains and country contexts.

To be eligible for inclusion, studies had to: (1) measure learning progress using test scores that could be standardized across studies using Cohen’s d, (2) base their estimates on empirical data collected since the onset of the COVID-19 pandemic, rather than making projections based on pre-COVID-19 data, and (3) be written in English, Danish, Dutch, French, German, Norwegian, Spanish or Swedish.

A total of 42 studies (including 291 estimates)…