that the causal effect of schooling is of a similar magnitude (Card, 1999). Moreover, schooling is associated with a broad variety of desirable outcomes, such as lower crime (Lochner and Moretti, 2004), higher civic participation (Milligan et al., 2004), improvements in child health (Currie and Moretti, 2003), and higher wellbeing (Easterbrook et al., 2015).

**Formal educational attainment varies substantially across rich and poor countries** . Figure IIa displays the average years of schooling of the adult population against GDP per worker. In 2015, the average worker in Norway was a high-school graduate (about 12 years of schooling), the corresponding average worker in Mozambique had not completed primary education (about 3 years of schooling). While most countries are relatively close to universal enrollment in primary schools, large gaps remain for what concerns secondary school enrollment (Figure IIb). A large development accounting literature quantifies the contribution of these gaps in educational attainment in explaining cross-country income differences. The emerging consensus is that this contribution is limited: even low-educated workers in rich countries are much richer than high-educated workers in poor countries, leaving little space for the educational composition to account for income gaps (see Rossi, 2020, for a review).

Figure II: Educational Attainment and Development <!-- Start of picture text --> (a) Average Years of Schooling (b) Enrollment Rate<br>15<br>1050 BDICAFCODMWINERLBRMOZ SLEHTITGOUGAMLI RWA GMBTZAYEMNPLZWESENBENZMBTJKCMRLSOKHMKENBGDSDNMRTCIVPAKCOGMMRKGZHNDNICVENGHAINDSYRVNMBLZLAOPHL BOL MDASLV MARGTM JAM SWZ IDNUKR JOR IRQMNGTUNNAMGUYARMECUALBPERPRYLKADZAEGYBRBCHNZAFFJIIRNCOLBRADOM BWA GABSRBTHACRIBGRMDVMEXMUSURYARGROUHRVCHLMYSKAZLVA PAN HUNRUSTURGRCLTUPOLSVKCYPESTPRTTTOSVNCZEMLTESPITANZLISRKORJPNFRAFINGBRBELTWNCANISLDNKDEUBHRAUSAUTSWEHKGNLDSAUKWTUSA NORCHEARESGPIRLLUX MACQAT 10080604020 BDI MWINERNERLBRMOZMOZ MDGBFABFAETHETHSLESLETGOTCDTCDMLIMLIRWAGMB NPLSENBENTJKCMRCMRLSOLSOKHMBGDSDNSTPSTPMRTCIV PAK PAK DJI DJIKGZ KGZ HND HND VENVENGHAGHAPSEPSECPVCPVBLZBLZLAOLAOPHLPHLBOLBOLMDAMDASLVSLVGTMGTMJAMJAMSWZSWZBTNBTN DMA IDNUZBUZBVCTVCTMNGARMECUECUAALBPERPERLKA L LCA DZABRBBRB GEO GEOBCAZAFZAFFJIGRDI RN COLCOLMKDAZESURSURBRABRADOMDOMSRBSRBTHACRI CRI ATGATGBGRBGRMNEMDVMEX MEX BLRBLRMUSMUS URY URYKNA ARG ARGROUROUHRVHRVCHLCHL MYS KAZKAZSYCSYCLVALVAPANPANHUNHUNRUSTURTURGRCGRCLTULTUPOLGNQSVKSVKCYPCYPESTESTPRTPRTSVNSVN BHS BHSCZECZEMLTMLTOMNOMN VGBESP ESPITAITANZLNZLISRISRKORKORFRAFRAFINFIN GBR GBRBELBEL CAN CANISLISLDNKDNKDEUDEUBHRBHRAUSAUSAUTAUT SWE HKGHKGNLDNLDSAUKWTKWTUSAUSABRNBRN NOR NORCHECHEAREIRLIRL Primary SecondaryLUXLUX MACMACQAT<br>7 8 9 10 11 12 7 8 9 10 11 12<br>Log GDP per worker in PPP (2015) Log GDP per worker in PPP (2015)<br>Net Enrollment Rate (%, 2015)<br>Average Years of Schooling (2015)<br><!-- End of picture text --> _Notes_ : Panel (a) plots average years of schooling in the population above 25 against log GDP per worker (in PPP terms) in 2015. Panel (b) plots the net enrollment rate in primary and secondary school against log GDP per worker (in PPP terms) in 2015. Average years of schooling is taken from Barro and Lee (2013), the enrollment rates are from the World Development Indicators, while GDP per worker is from version 9.0 of the Penn World Tables (Feenstra et al., 2015).

**More recent work, however, points to large gaps in learning achievements and educational quality across countries, which compound the effect of gaps in schooling quantity** . Figure III displays the average learning scores of primary and secondary school students from the Harmonized Learning Outcomes Database (Angrist et al., 2021a), a collection of average scores in standardized tests administered across 164 countries, against log GDP per worker. Students in rich countries vastly outperform their peers in poor countries, conditional on a given level of educational attainment; as a result, the vast majority of the young generations in the developing world do not achieve the skills needed to participate effectively in modern economies (Gust et al., 2024). In addition, Singh (2019) exploits panel data to show that an

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