Table 4 Risk ratios \(G_{+}/G_{-}\) for high fatigue (\(\texttt {SP} \ge 6\)) and sleepiness (\(\texttt {KSS} \ge 7\)) scores and their 95% confidence intervals for all workload variables with statistically significant Pearson’s correlations with SP and/or KSS (see Table 2). Also shown the mean (or median), the threshold values and the actual fraction of excluded events for each distribution. (*) For practical purpose the DT threshold was fixed at 44h.
Variable | Risk ratio (\(G_{+}/G_{-}\)) | Mean or | Threshold | Fraction of | |
|---|---|---|---|---|---|
\(\texttt {SP} \ge 6\) | \(\texttt {KSS} \ge 7\) | median | values | excluded events | |
DT | 7.111 (1.659–30.481) | 2.844 (1.503–5.384) | 25.4h | 43.9h* | 2.3% |
\(N_{NS}\) | 0.960 (0.287–3.209) | 0.995 (0.495–2.003) | 2 | 4 | 0% |
\(N_{CREW}\) | 1.677 (0.658–4.270) | 2.515 (1.399–4.519) | 7 | 15 | 1.9% |
\(N_{SIT}\) | 1.691 (0.668–4.280) | 1.249 (0.711–2.196) | 2 | 5 | 2.3% |
\(N_{CREW}+N_{SIT}\) | 1.810 (0.695–5.120) | 2.450 (1.380–4.349) | 9 | 19 | 1.9% |
\(N_{REST}\) | 1.521 (0.607–3.813) | 0.718 (0.395–1.304) | 1 | 4 | 0.8% |
\(N_{DUTY}\) | 0.900 (0.304–2.666) | 1.513 (0.866–2.644) | 1 | 3 | 1.5% |
