Socioeconomic Status
Socioeconomic status is classified based on the parents’ health insurance premium, which is reflective of the household income. The status is categorized into the following quartile ranges: low (KRW 0−43,260,000), mid-low (KRW 43,261,000−74,555,000), mid-high (KRW 75,556,000−122,370,000), and high (KRW 122,371,000 or more) .