Frequency of symptom endorsement during the HIA1, including individual positive predictive values
| Cases | Concussion confirmed (PPV) | Clinical judgement applied (%) | Clinical judgement correct (%) | Theoretical accuracy, % | Real-life accuracy, % | Ratio | |
| Feel in a fog | 75 | 70 (93.3) | 3 (4.0) | 1 (33.2) | 65.7 | 65.7 | 1.00 |
| Nausea or vomiting | 29 | 26 (89.7) | 2 (6.9) | 1 (50) | 62.0 | 62.0 | 1.00 |
| Slowing down | 95 | 82 (86.3) | 11 (11.6) | 4 (36.4) | 66.1 | 65.8 | 1.00 |
| Blurred vision | 96 | 82 (85.4) | 5 (5.2) | 5 (100) | 66.0 | 66.5 | 1.01 |
| Light or noise sensitivity | 29 | 24 (82.8) | 3 (10.3) | 1 (33.3) | 61.6 | 61.5 | 1.00 |
| Headache | 138 | 113 (81.9) | 13 (9.4%) | 9 (69.2) | 67.8 | 68.2 | 1.01 |
| Pressure in head | 115 | 94 (81.7) | 13 (11.3) | 7 (53.8) | 66.5 | 66.5 | 1.00 |
| Dizziness | 126 | 102 (81.0) | 11 (8.7) | 7 (63.6) | 66.9 | 67.2 | 1.00 |
| Unwell | 47 | 38 (80.9) | 4 (8.5) | 3 (75) | 62.5 | 62.7 | 1.00 |
| Any symptom | 320 | 249 (78) | 45 (14.1) | 30 (66.7) | 75.8 | 77.2 | 1.02 |
| High-risk symptom present | 194 | 164 (84.5) | 18 (9.3) | 10 (55.6) | 71.9 | 72.1 | 1.00 |
| Low-risk symptom present but excluding high risk | 126 | 85 (67.5) | 27 (27.4) | 20 (74.1) | 63.9 | 65.0 | 1.02 |
PPV, positive predictive value.