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Table 2 Sample sizes a required for a 95% confidence interval width of 0.10 around the sensitivity estimate adjusted for the over-sampling of adverse event (AE) positive patients induced by the study design

From: Accuracy of using automated methods for detecting adverse events from electronic health record data: a research protocol

Adverse event (AE) indicator Estimated incidence rate b Desired specificity Expected corrected sensitivity (range) Expected positive predictive value (range) Optimal sampling test positivity rate Optimal sample sizes c
No. of AE positive patients No. of AE negative patients Total no. of patients sampled
Nosocomial pneumonia (NP) 0.05 0.95 0.85 0.80 0.10290 191 1,980 2,171
    0.90 0.10290 94 979 1,073
   0.90 0.80 0.07104 237 3,099 3,336
    0.90 0.07104 117 1,532 1,649
  0.98 0.85 0.80 0.06667 119 1,975 2,094
    0.90 0.06667 59 976 1,035
   0.90 0.80 0.04545 148 3,111 3,259
    0.90 0.04545 73 1,538 1,611
Central venous catheter-associated blood stream infection (CVC-BSI) 0.05 0.95 0.85 0.80 0.10290 191 1,980 2,171
    0.90 0.10290 94 979 1,073
   0.90 0.80 0.07104 237 3,099 3,336
    0.90 0.07104 117 1,532 1,649
  0.98 0.85 0.80 0.06667 119 1,975 2,094
    0.90 0.06667 59 976 1,035
   0.90 0.80 0.04545 148 3,111 3,259
    0.90 0.04545 73 1,538 1,611
In-hospital fall 0.07 0.95 0.85 0.80 0.10290 133 1,379 1,512
    0.90 0.10290 66 682 747
   0.90 0.80 0.07104 165 2,161 2,327
    0.90 0.07104 82 1,068 1,150
  0.98 0.85 0.80 0.06667 83 1,376 1,458
    0.90 0.06667 41 680 721
   0.90 0.80 0.04545 103 2,170 2,273
    0.90 0.04545 51 1,073 1,124
  1. aSample size calculations are based on [58]. bBased on the literature and expert opinion. cValues in italics represent the worst case scenario for a given AE indicator.