| Code | Description | Upper Code | Notes |
| 1 | Face to face interview-PAPI | ||
| 2 | Face to face interview-CAPI | ||
| 3 | CATI, telephone interview | ||
| 4 | Self-administered by respondent | ||
| 5 | Computer assisted web interviewing-CAWI | ||
| 6 | Face to face interview-PAPI with proxy | ||
| 7 | Face to face interview-CAPI with proxy | ||
| 8 | CATI, telephone interview with proxy | ||
| 9 | Self-administered by respondent with proxy | ||
| 10 | Computer assisted web interviewing-CAWI with proxy |