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Table 3 Detection metrics. Mean probability of detection (P D ), median days to detection (T D ) and thousand symptomatic people (Sym) at median time to detection per syndromic surveillance system and outbreak size under the current coverage and a hypothetical 100% coverage for each syndromic surveillance system

From: A methodological framework for the evaluation of syndromic surveillance systems: a case study of England

   Estimated current coverage Hypothetical 100% coverage
   Size 1 Size2 Size 3 Size 1 Size2 Size 3
System-indicator Coverage (%) P D T D Sym P D T D Sym P D T D Sym P D T D Sym P D T D Sym P D T D Sym
Influenza
 EDSSS-influenza like illness 7 1.00 158 105.6 1.00 87 110.9 1.00 64 115.0 1.00 97 7.4 1.00 56 7.8 1.00 42 8.1
    (81–248)    (44–136)    (32–99)    (52–161)    (31–91)   (23–68)   
 GPIHSS-influenza like illness 64 1.00 102 9.4 1.00 61 12.6 1.00 47 14.2 1.00 93 6.1 1.00 56 8.1 1.00 43 9.1
    (56–162)    (33–96)    (25–73)    (51–148)    (31–89)    (23–68)  
 GPOOHSS-influenza like illness 65 1.00 146 53.4 1.00 81 59.5 1.00 59 63.3 1.00 136 34.7 1.00 76 38.7 1.00 56 41.1
    (74–222)    (41–124)    (30–91)    (70–208)    (39–116)    (29–86)  
 NHS-111 cold-flu 100 1.00 140 72.0 1.00 79 79.6 1.00 58 84.0 1.00 140 72.0 1.00 79 79.6 1.00 58 84.0
    (76–232)    (42–128)    (30–94)    (76–232)    (42–128)    (30–94)  
Cryptosporidiosis (Location A)
 EDSSS diarrhoea 15 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - -
 GPIHSS diarrhoea 64 0.14 - - 0.24 - - 0.84 8 4.4 0.25 - - 0.39 - - 0.92 6 3.6
          (2–33)          (2–24)  
 GPOOHSS diarrhoea 65 0.18 - - 0.33 - - 0.95 4 2.4 0.34 - - 0.51 7 0.9 0.99 3 1.8
          (2–11)       (3–20)    (1–9)  
 NHS-111 diarrhoea 100 0.00 - - 0.00 - - 0.52 7 5.7 0.00 - - 0.00 - - 0.52 7 5.7
          (3–21)          (3–21)  
Cryptosporidiosis (Location B)
 EDSSS diarrhoea 23 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - -
 GPIHSS diarrhoea 95 0.63 10 0.4 0.76 7 0.6 1.00 3 1.4 0.65 9 0.4 0.77 7 0.6 1.00 3 1.4
    (3–47)    (2–37)    (1–7)    (3–47)    (2–36)    (1–7)  
 GPOOHSS diarrhoea 7 0.05 - - 0.12 - - 0.83 4 3.4 0.93 4 0.2 0.97 3 0.3 1.00 2 0.6
          (2–12)    (2–10)    (2–8)    (1–3)  
 NHS-111 diarrhoea 100 0.10 - - 0.23 - - 0.89 4 3.2 0.10 - - 0.23 - - 0.89 4 3.2
          (2–13)          (2–13)  
Cryptosporidiosis (Location C)
 EDSSS diarrhoea 47 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - - 0.00 - -
 GPIHSS diarrhoea 86 0.62 12 0.4 0.74 9 0.6 0.99 3 1.7 0.67 11 0.4 0.78 9 0.6 1.00 3 1.5
    (3–53)    (3–47)    (1–9)    (3–51)    (3–41)    (1–8)  
 GPOOHSS diarrhoea 33 0.44 - - 0.61 6 0.8 0.99 3 1.7 0.85 5 0.4 0.94 4 0.4 1.00 2 0.8
       (3–17)    (1–8)    (2–13)    (2–11)    (1–4)  
 NHS-111 diarrhoea 100 0.06 - - 0.18 - - 0.86 4 3.3 0.06 - - 0.18 - - 0.86 4 3.3
          (2–14)          (2–14)  
  1. T D and number of symptomatic people for P D ≤0.5 are not presented
  2. The values in brackets indicate the 95% prediction intervals for T D