Academic polarization of students in high and low academic ranks was found to have worsened in schools that had reduced class hours due to the outbreak of the COVID-19 pandemic.

The finding was outlined in a study conducted by Hyuncheol Bryant Kim, an associate professor at Hong Kong University of Science and Technology, and two professors from Yonsei University.

First, it found that the number of school days throughout high schools in South Korea in 2020 had dropped to an average of 104, compared to the legally mandated 190 in pre-pandemic 2019.

Based on an academic achievement assessment of second-year high school students, the study found that the number of middle-ranking students in Korean language fell three-point-one percentage points in schools with fewer than 100 days of class compared to those that had more than 100 days.

The number of students in the high and low ranks rose by one percentage point and two-point-one percentage points, respectively.

In math, the middle rank declined four-point-one percentage points, while the high and low ranks jumped one-point-four and two-point-seven percentage points, respectively.

The researchers conjectured that the gap widened due to high-ranking students continuing their studies through alternative learning on days they didn't attend school, compared to those in the low rank who didn't spend time on their studies.