Effect of the Duration of Preschool Attendance on Academic Achievements—Evidence from PISA 2018

Research has consistently demonstrated the positive influence of preschool on students' development, with a longer duration of attendance generally correlating with improved academic achievements. However, according to the marginal utility theory, it is conceivable that there might exist an optimal duration of preschool attendance to maximize academic benefits. Currently, the optimal duration remains uncertain, and it may vary depending on the distinctive preschool characteristics of different countries. Therefore, the aim of this study was to examine the effects of different durations of preschool attendance on academic achievements in mathematics, reading, and science and explore the optimal duration in B-S-J-Z (China), Italy, New Zealand, Denmark, and Sweden, employing the generalized propensity score (GPS) method to control for confounding factors based on the Programme for International Student Assessment (PISA) 2018. The findings revealed a generally inverted U-shaped relationship between the duration of preschool attendance and academic achievements. Moreover, the optimal duration varied among the five countries: students in New Zealand benefited the most from attending preschool for 2 years, 3 years in Italy, and 4 years in B-S-J-Z (China), Denmark, and Sweden. The findings offer practical guidance for parents and educators in these countries to tailor their children's duration of preschool attendance for the enhancement of academic achievements.