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Table 2 Adjusted TRISS misclassification rate and adjusted w-statistic in 163 major trauma

From: Evaluation of trauma care using TRISS method: the role of adjusted misclassification rate and adjusted w-statistic

TRISS Method deaths survivors
  Od Os
Positive (P(s) < 50%) TP FP
  a = 39    b = 0
  EOd Us
Negative (P(s) > 50%) FN TN
  c = 34    d = 90
     c1 = Pd = 30 EOs
  c2 = nonPd = 4  
  Ud = Pd+nonPd  
  1. Differences between misclassification rate and w-statistic and adjusted misclassification rate and adjusted W statistic where Pd are identified. Adjusted misclassification rate drops from previous 20.8% on reliable 2.4%.
  2. Misclassification rate = (b + c)/N = (0+34)/163 = 20.8%
  3. Adjusted misclassification rate = (b+c-Pd)/N = (0+34-30)/163 = 4/163 = 2.4%
  4. W statistic = (b-c)/N = (0–34)/163 = -20.8%
  5. Adjusted w- statistic = (b - Pd)/N = (0–30)/163 = -18.4%