Match events responsible for head injuries requiring HIAs
| Event | HIA event | Average events per match | Propensity (95% CI), HIAs per 1000 events | HIA period (95% CI), matches per HIA event |
| Tackles | 464 | 158 | 1.94 (1.77 to 2.12) | 3.1 (2.8 to 3.4) |
| Kick contests | 14 | 5.9 | 1.57 (0.93 to 2.65) | 108.3 (64.1 to 182.9) |
| Mauls | 11 | 10.4 | 0.70 (0.39 to 1.26) | 137.8 (76.3 to 248.9) |
| Scrums | 9 | 16.3 | 0.36 (0.19 to 0.69) | 168.4 (87.6 to 323.7) |
| Rucks | 73 | 162.9 | 0.30 (0.24 to 0.37) | 20.8 (16.5 to 26.2) |
| Lineouts | 2 | 25.2 | 0.05 (0.01 to 0.20) | 758.0 (189.6 to 3030.9) |
| Open play | 38 | n/a | n/a | n/a |
HIA, head injury assessment; n/a, not applicable.