| Value | Category |
|---|---|
| -999 | Refuse to answer |
| -888 | Don’t know |
| -111 | Not applicable |
| 1 | None |
| 2 | Primary school |
| 3 | Middle/JSS/JHS |
| 4 | SSS/SHS |
| 5 | O/A level |
| 6 | Vocational/Technical/Commercial |
| 7 | Post-secondary certificates |
| 8 | Diploma/HND |
| 9 | Bachelor degree |
| 10 | Masters |
| 11 | PhD |
| 12 | Others |