Educational levels of parents were categorized into primary school, secondary school, college and above.
Education was measured by the highest level of education completed and categorized into "elementary school not completed", "elementary school completed", "vocational education/general secondary education", and "college or university education".
Education was measured by asking for the highest level of education completed and was categorized into "elementary school not completed", "elementary school completed", "vocational education/general secondary education", and "college or university education".
The level of education was categorized into basic schooling (7 10 years), upper secondary education (high school/vocational school), and tertiary education (college/university).
Education was categorized into below high school, high school, or above high school education.
Education was categorized into below high school, high school, or above high school levels.
Educational level was categorized into low (elementary school and junior high school), middle (high school, technical or vocational school), or high (university or college).
For educational status, we categorized into less high school, high school graduate and college graduate.
Educational attainment was categorized into less than high school, high school diploma, or greater than high school.
It was categorized into "primary/upper secondary school" versus "≥1 year at college/university".
