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Table 1 Sensitivities, specificities, and detection times of various alert thresholds in Chabahar District, south-east Iran (21 Mar 2003-19 Mar 2008)

From: Defining and detecting malaria epidemics in south-east Iran

  Earliest week epidemic detected (n = 13)
Thresholds Sensitivity (percent) Specificity (percent) 1st 2nd 3rd ≥ 4th
Percentiles (1 week span)       
> 60% 93.7 81.5 12 1 0 0
> 70% 93.7 85.5 12 1 0 0
> 75% 87.4 91.2 10 3 0 0
> 80% 74.8 94.3 5 6 1 1
Percentiles (3 week span)       
> 60% 96.5 81.7 12 1 0 0
> 70% 95.1 87.5 12 1 0 0
> 75% 94.4 90.5 12 1 0 0
> 80% 90.9 93.1 11 2 0 0
> 85% 78.3 95.6 6 6 1 0
Mean count + SD's (1 week span)       
> mean + 0.25SD 97.2 89.4 12 1 0 0
> mean + 0.50SD 93.7 93.4 10 3 0 0
> mean + 1.00SD 81.8 97.2 6 6 1 0
> mean + 1.50SD 69.9 98.2 4 6 2 1
Mean count + SD's (3 week span)       
> mean + 0.25SD* 99.3 90.0 12 1 0 0
> mean + 0.50SD 93.7 93.9 10 3 0 0
> mean + 1.00SD 83.9 97.3 7 6 0 0
> mean + 1.50SD 72.7 98.4 5 6 1 1
Mean log(count + 1) + SD's (1 week span)       
> mean + 0.25SD 98.6 78.2 12 1 0 0
> mean + 0.50SD 96.5 84.5 12 1 0 0
> mean + 1.00SD 84.6 93.0 9 3 1 0
> mean + 1.50SD 70.6 97.5 4 6 2 1
Mean log(count + 1) + SD's (1 week span)       
> mean + 0.25SD 100.0 77.1 13 0 0 0
> mean + 0.50SD 100.0 83.5 13 0 0 0
> mean + 1.00SD 93.0 92.9 10 3 0 0
> mean + 1.50SD 74.1 97.7 5 6 1 1