Table 1.
Descriptive criteria of studies included.
| Authors(Country) | Duration of school closure | Type of school | Sample size | Subjects | Statistical method | General effect | Differential effects |
|---|---|---|---|---|---|---|---|
| Clark et al.(China) | 7 weeks | Secondary | 1,835 | Reading, Mathematics, English, Politics, History | DiD Regression | −0.22 SD | Larger effect in girls Larger effect in low-achieving students |
| Depping et al.(Germany) | 8 weeks | Elementary and Secondary | ~27,500 | Reading, Mathematics | Difference Analyses | 0 SD to +0.05 SD (reading)−0.03SD to −0.02 SD (mathematics) | — |
| Engzell et al.(Netherlands) | 8 weeks | Elementary and Secondary | 350,000 | Reading, Mathematics | DiD Regression | −0.09 SD (reading)−0.14 SD (mathematics) | +60% learning loss in low-SES students |
| Gore et al. (Australia) | 8 weeks | Elementary | >4,800 | Reading, Mathematics | Linear Mixed Models | +0.04 SD (reading)+0.06 SD (mathematics) | Grade 3 in mathematics:−0.16 SD for low school-level SES, +0.15 SD for medium school-level SES |
| Kuhfeld, Ruzek, et al.(USA) | 8 weeks | Elementary and Secondary | ~7 Million | Reading, Mathematics | Change Score Analyses | −0.13 SD to−0.25 SD (mathematics) | Likely differences for different ethnicities |
| Maldonado and De Witte(Belgium) | 7 weeks | Elementary | > 4,000 | Reading, Mathematics, Social Sciences, Science, French | DiD Regression | −0.29 SD (reading)−0.19 SD (mathematics) | Larger effect in low-SES students |
| Meeter(Netherlands) | 8 weeks | Elementary | ~95,000 | Mathematics | ANOVA | +0.20 SD | — |
| Schult et al.(Germany) | 8 weeks | Secondary | ~80,000 | Reading, Mathematics | Change Score Analyses | −0.07 SD (reading)−0.09 SD to−0.03 SD (mathematics) | Larger effect on reading in high-performing students, larger effect on mathematics in low-performing students |
| Spitzer and Musslick (Germany) | 8 weeks | Elementary and Secondary | > 2,500 | Mathematics | Linear Mixed Models | −2.43% (error rate) | Larger improvements in low-achieving students |
| Tomasik et al.(Switzerland) | 8 weeks | Elementary and Secondary | 26,685 | Reading, Mathematics | Growth Curve Models | −0.37 SD (elementary school)−0.10 SD (secondary school) | Larger effect in younger students, larger effect in high-performing students |
| van Der Velde et al.(Netherlands) | 8 weeks | Secondary | 133,450 | French | Linear Mixed Models | +0.25 SD (correct solutions to open questions) | – |