Differences in characteristics between students completing all surveys and those completing baseline only
| Covariate | Category | Total | Baseline data only |
| N (%) n=3337 | N (%) n=1040 | ||
| School size | Small | 1574 (47.17) | 542 (52.12) |
| Large | 1763 (52.83) | 498 (47.88) | |
| School neighbourhood deprivation | Low score | 1696 (47.83) | 525 (50.48) |
| High score | 1741 (52.17) | 515 (49.52) | |
| Free school meal eligibility | Low score | 1663 (49.84) | 527 (50.67) |
| High score | 1674 (50.16) | 513 (49.33) | |
| Student gender | Female | 1644 (50.15) | 515 (50.54) |
| Male | 1634 (49.85) | 504 (49.46) | |
| Student ethnicity | White British | 1383 (41.46) | 446 (43.34) |
| Other | 1921 (58.14) | 583 (56.66) | |
| Family structure | Two parents | 2388 (71.97) | 647 (62.75) |
| Other | 930 (28.03) | 384 (37.25) | |
| Parental working | Not in work | 287 (10.57) | 115 (14.32) |
| In work | 2429 (89.43) | 688 (85.68) | |
| Family affluence | Low affluence | 1194 (36.81) | 371 (36.88) |
| High affluence | 2050 (63.19) | 365 (63.12) |