| Value | Category |
|---|---|
| -99 | Refuse to answer |
| -98 | Difficult to answer/Don't remember |
| -97 | Don't know/No information |
| -9 | Interrupted interview |
| -7 | Legal Skip |
| -3 | Interviewer error |
| 1 | Primary and lower |
| 2 | Basic (grades 8-9) |
| 3 | General secondary |
| 4 | Pre-vocational |
| 5 | Vocational (college) |
| 6 | Higher education |
| 7 | Postgraduate |