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Table 1 Characteristics of study data and sizes of data sets

From: The advanced machine learner XGBoost did not reduce prehospital trauma mistriage compared with logistic regression: a simulation study

Characteristics NTDB SweTrau
Total number of observations 813,567 30,577
Number of missing observations 422,416 10,411
Number of included observations 368,810 16,547
Proportion major trauma 0.21 0.12
Proportion female 0.38 0.35
Age (median-IQR) 51 [30, 69] 41 [25 59]
GCS Category NTDB proportion of observations SweTrau proportion of observations
13–15 0.9098 0.9173
9–12 0.0384 0.0401
6–8 0.0175 0.018
4–5 0.0061 0.009
3 0.0283 0.0156
RR Category NTDB proportion of observations SweTrau proportion of observations
30–67 0.0191 0.0543
10–29 0.9677 0.9407
6–9 0.0063 0.0036
0–5 0.0021 0.0011
SBP Category NTDB proportion of observations SweTrau proportion of observations
90–300 0.9707 0.9798
76–89 0.0192 0.0126
50–75 0.0091 0.0068
1–49 0.0011 0.0007
Size training sets (events per free parameter) NTDB SweTrau
10 714 1250
25 1786 3125
100 7143 12,500
1000 71,429 Missing
Size validation and test sets NTDB SweTrau
(200/proportion events) 952 1667
  1. NTDB, National Trauma Data Bank; SweTrau, Swedish Trauma Registry; GCS, Glasgow Coma Scale; RR, Respiratory Rate; SBP, Systolic Blood Pressure