Lower middle-class households with children in high school saw private education expenditure grow faster than their income in the past 12 years, a study showed Sunday.

The study by the Korean Educational Development Institute said household spending on after-school education increased for students of all ages from 2007 to 2018, largely due to higher income levels.

But income elasticity, which indicates the connection between income and spending on private education, varied significantly, the study found.

Income elasticity for private education spending for households with children in high school stood at an average of 0.9805, while it stood at 0.6808 and 0.7714 for families with elementary school and middle school kids, respectively.

A figure closer to 1 means willingness to spend money on after-school education closely correlates to family income, while a figure close to zero means changes in income have little impact on private education spending. 

The report found that income elasticity was highest at 1.2151 for households earning between 3 million won ($2,418) and 4 million won per month with children in high school.

“It is difficult to trigger high-income households to cut their expenditure on private education, but for low-income ones, that spending can be curbed with improved public education, after-school activities and more,” said Kim Hyun-chul, an industrial organization professor at Sungkyunkwan University, who authored the report.

By Ko Jun-tae (ko.juntae@heraldcorp.com)