Learning loss due to school closures during the COVID-19 pandemic

During the pandemic-induced lockdown in 2020, schools in many countries were forced to close for extended periods. It is of great policy interest to know whether students are able to have their educational needs met under these circumstances and to identify groups at special risk. In this study, we have addressed this question with uniquely rich data on primary school students in The Netherlands. There is clear evidence that students are learning less during lockdown than in a typical year. These losses are evident throughout the age range we study and across all of the three subject areas: math, spelling, and reading. The size of these effects is on the order of 3 percentile points or 0.08 SD, but students from disadvantaged homes are disproportionately affected. Among less-educated households, the size of the learning slide is up to 60% larger than in the general population.

Are these losses large or small? One way to anchor these effects is as a proportion of gains made in a normal year. Typical estimates of yearly progress for primary school range between 0.30 and 0.60 SD. In their projections of learning loss due to the pandemic, the World Bank assumes a yearly progress of 0.40 SD. We validate these benchmarks in our data by exploiting variation in testing dates during comparison years and show that test scores improve by 0.30 to 0.40 percentiles per week, equivalent to 0.31 to 0.41 SD annually (SI Appendix, section 4.3). Using the larger benchmark, a treatment effect of 3.16 percentiles would translate into 3.16/0.40 = 7.9 wk of lost learning—nearly exactly the same period that schools in The Netherlands remained closed. Using the smaller benchmark, learning loss exceeds the period of school closures (3.16/0.30 = 10.5 wk), implying that students regressed during this time. At the same time, some studies indicate a progress of up to 0.80 SD annually at the low extreme of our age range, which would indicate that remote learning operated at 50% efficiency.

Another relevant source of comparison is studies of how students progress when school is out of session for summer. This literature reports reductions in achievement ranging from 0.001 to 0.010 SD per school day lost. Our estimated treatment effect translates into 3.16/35 = 0.09 percentiles or 0.002 SD per school day and is thus on the lower end of that range. Although early influential studies also found that summer is a time when socioeconomic learning gaps widen, this finding has failed to replicate in more recent studies or in European samples. However, there are limits to the analogy between summer recess and forced school closures, when children are still being expected to learn at a normal pace. Our results show that learning loss was particularly pronounced for students from disadvantaged homes, confirming the fears held by many that school closures would cause socioeconomic gaps to widen.

We have described The Netherlands as a best-case scenario due to the country’s short school closures, high degree of technological preparedness, and equitable school funding. However, this does not mean that circumstances were ideal. The short duration of school closures gave students, educators, and parents little time to adapt. It is possible that remote learning might improve with time. At the very least, our results imply that technological access is not itself sufficient to guarantee high-quality remote instruction. The high degree of school autonomy in The Netherlands is also likely to have created considerable variation in the pandemic response, possibly explaining the wide school-level variation in estimated learning loss (SI Appendix, section 7.9).

Are these results a temporary setback that schools and teachers can eventually compensate? Only time will tell whether students rebound, remain stable, or fall farther behind. Dynamic models of learning stress how small losses can accumulate into large disadvantages with time. Studies of school days lost due to other causes are mixed—some find durable effects and spillovers to adult earnings, while others report a fadeout of effects over time. If learning losses are transient and concentrated in the initial phase of the pandemic, this could explain why results from the United States appear less dramatic than first feared. Early estimates suggest that grades 3 to 8 students more than 6 mo into the pandemic underperformed by 7.5 percentile points in math but saw no loss in reading achievement.

Nevertheless, the magnitude of our findings appears to validate scenarios projected by bodies such as the European Commission and the World Bank. This is alarming in light of the much larger losses projected in countries less prepared for the pandemic. Moreover, our results may underestimate the full costs of school closures even in the context that we study. Test scores do not consider children’s psychosocial development, either societal costs due to productivity decline or heightened pressure among parents. Overall, our results highlight the importance of social investment strategies to “build back better” and enhance resilience and equity in education. Further research is needed to assess the success of such initiatives and address the long-term fallout of the pandemic for student learning and wellbeing.