Intervention effects on student primary and secondary outcomes at the final follow-up before and after adjusting for potential mediators at the interim follow-up
| Continuous student outcomes | Arm | Unadjusted effect | Adjusted effect (baseline covariates) | Adjusted effect (baseline covariates plus student view of school climate) | Adjusted effect (baseline covariates plus friends’ contact with police in last year) | Adjusted effect (baseline covariates plus staff view of school organisational climate) | ||||||
| Control Mean (SE) | Intervention Mean (SE) | Difference (95% CI) | P value | Difference (95% CI) | P value | Difference (95% CI) | P value | Difference (95% CI) | P value | Difference (95% CI) | P value | |
| Bullying victimisation (GBS overall score) | 0.34 (0.02) | 0.29 (0.02) | −0.03 (−0.06 to −0.00) | 0.039 | −0.03 (−0.06 to −0.00) | 0.044 | −0.04 (−0.08 to −0.01) | 0.007 | −0.04 (−0.07 to −0.01) | 0.016 | −0.02 (−0.07 to 0.03) | 0.380 |
| Aggression perpetration (ESYTC overall score) | 4.33 (0.20) | 4.04 (0.21) | −0.07 (−0.38 to 0.25) | 0.684 | −0.13 (−0.43 to 0.18) | 0.421 | −0.20 (−0.52 to 0.13) | 0.229 | −0.12 (−0.44 to 0.20) | 0.469 | 0.03 (−0.58 to 0.64) | 0.917 |
| Quality of life (PedsQL overall score) | 78.82 (0.54) | 80.65 (0.55) | 1.16 (0.41 to 1.90) | 0.002 | 1.44 (0.70 to 2.17) | <0.001 | 1.42 (0.64 to 2.21) | <0.001 | 1.26 (0.49 to 2.03) | 0.001 | 1.43 (0.09 to 2.77) | 0.036 |
| Psychological functioning (SDQ total difficulties score | 12.20 (0.18) | 11.51 (0.19) | −0.51 (−0.80 to −0.22) | <0.001 | −0.54 (−0.83 to −0.25) | <0.001 | −0.62 (−0.92 to −0.31) | <0.001 | −0.54 (−0.85 to −0.24) | <0.001 | −0.38 (−0.92 to 0.17) | 0.170 |
| SWEMWBS total well-being index) | 22.88 (0.19) | 23.32 (0.19) | 0.27 (−0.06 to 0.60) | 0.115 | 0.33 (0.00 to 0.66) | 0.048 | 0.27 (−0.08 to 0.62) | 0.141 | 0.23 (−0.13 to 0.58) | 0.210 | 0.21 (−0.36 to 0.80) | 0.463 |
| Health utility (CHU9D overall score) | 0.85 (0.00) | 0.86 (0.01) | 0.01 (−0.00 to 0.01) | 0.244 | 0.01 (−0.00 to 0.01) | 0.080 | 0.00 (−0.00 to 0.01) | 0.153 | 0.00 (−0.00 to 0.01) | 0.217 | 0.00 (−0.01 to 0.01) | 0.570 |
| Age of sexual debut | 13.11 (0.43) | 12.54 (0.49) | −0.58 (−1.97 to 0.81) | 0.416 | −0.35 (−1.48 to 0.78) | 0.541 | −0.24 (−1.48 to 1.00) | 0.703 | −0.40 (−1.65 to 0.84) | 0.525 | −0.51 (−2.03 to 1.01) | 0.513 |
| Bullying perpetration (MAS bullying subscale score) | 2.75 (0.21) | 2.33 (0.21) | −0.28 (−0.84 to 0.29) | 0.334 | −0.26 (−0.57 to 0.05) | 0.097 | −0.29 (−0.57 to −0.00) | 0.047 | −0.16 (−0.45 to 0.13) | 0.279 | −0.27 (−0.69 to 0.14) | 0.193 |