The paper is structured as follows. The next section provides a brief review of relevant literature, while the following section describes what’s new in the analytical framework and the empirical methodology used in this global update. The two subsequent sections present the results and discuss the main findings, respectively. The final section concludes. The appendices provide methodological details and a detailed description of the main indicators.

# **What Do We Know about School Closures, Mitigation Effectiveness, and Learning Losses?**

This section reviews what we have learned so far about the extent of school closures during COVID-19, the likely effectiveness of remote learning, and the learning losses that resulted. This information all feeds into the data and assumptions used in the simulation model.

## Schools Closures Varied across Contexts

During peak school closures in April 2020, 1.6 billion children, or 94% of the world’s students, were out of school. Over a billion of these children live in low- and middle-income countries. According to the latest results from the UNESCO school closure tracker, documented in Figure A1 in the annex, the length of school closures has varied greatly across regions, with full closures in low- and middle-income countries lasting longer than those in high-income countries. Globally, between February 2020 and February 2022, schools were fully closed for 141 days on average, while partial school closures also lasted for 141 days (Table A1). Partial closures may involve schools offering face-to-face instruction only in certain areas, or for certain grades, or via a hybrid model where only some students receive in-person instruction at a time.

## Remote Learning Provision Varied across Contexts

After COVID-19 prompted school closures in early 2020, many countries pivoted towards providing remote instruction. A 2021 World Bank report documents countries’ experiences with remote learning during the pandemic, and concludes that many countries used multi-modal strategies by combining the use of, for example, internet, TV, radio, as well as printed materials, but there were differences across income groups, with high-income countries more likely to rely on internet-based solutions. Despite provision of remote learning solutions, many countries, especially low-income countries, struggled to ensure take-up of remote learning initiatives. Many countries even found themselves in a “remote learning paradox,” in which they adopted remote learning solutions that were not suited to the needs of most of the student population due to lack of devices or connectivity issues.

## Learning Losses Are Large and Inequitable

The State of the Global Education Crisis report by World Bank, UNESCO, and UNICEF (2021) reviews the literature on learning losses and concludes that learning losses have been large and are unequal, both between and within low-, middle-, and high-income countries. Based on a review of the existing evidence in low- and middle-income countries, the report suggests that the learning losses are roughly proportional to the length of the school closures, but that there is a great deal of heterogeneity across and within countries. Recent analysis by Moscoviz and Evans (2022) suggests that learning losses are concentrated primarily among children from poorer households. Even in high-income countries that had existing technological infrastructure for deployment of remote learning, learning losses were substantial. There is empirical evidence on learning losses from a diverse set of countries, ranging from Belgium and the United Kingdom to India and Brazil. For example, in the Indian state of Karnataka, the share of Grade 3 students in public schools who could perform simple subtraction fell by 8 percentage points between 2018 and 2020. Similarly, students in São Paulo in Brazil learnt only 28% of what they would have in face-to-face classes. In Ethiopia, <mark>children in grade</mark> 3