Table 3.
Specificity of reporting thresholds when used alone or in a serial approach.
| Thresholds | Specificity % | False alarm (FA) rate. Number FA/day X 1000 farms |
|---|---|---|
| Mortality | ||
| Mortality % ≥0.5 (1 day)a | 100.0 | 0.00 (0.00–0.27) |
| Mortality % ≥0.25 (1 day)a | 90.3 | 0.22 (0.05–0.65) |
| Mortality % ≥0.25 (2 day)b | 100.0 | 0.00 (0.00–0.27) |
| Ratio >2.9b | 71.0 | 0.79 (0.33–1.26) |
| CUSUMb | 35.5 | 2.25 (1.53–2.97) |
| Mortality % >0.08/0.13b | 87.1 | 0.39 (0.02–0.77) |
| Egg production | ||
| Ratio production <0.94b | 38.7 | 2.37 (1.59–3.15) |
| CUSUMb | 22.7 | 3.23 (2.25–4.22) |
| Serial use of thresholdsc | ||
| Ratio-mortality | ||
| Mortality % >0.08/0.13 | 97.0 | 0.07 (0.00–0.41) |
| CUSUM- egg | 100.0 | 0.00 (0.00–0.27) |
| Ratio production | 97.0 | 0.07 (0.00–0.41) |
| CUSUM-mortality | ||
| Mortality % >0.08/0.13 | 93.5 | 0.15 (0.02–0.53) |
| CUSUM-egg | 93.5 | 0.15 (0.02–0.53) |
| Ratio production | 96.8 | 0.07 (0.00–0.41) |
aAn alarm in triggered the first day the threshold is passed.
bFor these thresholds an alarm is triggered when the threshold is passed for at least two consecutive days.
cA screening threshold (Ratio-mortality or CUSUM-mortality) triggers an alarm when a threshold is passed for at least two consecutive days. The confirmation threshold needs to be passed for only one day following the alarm triggered by the screening.