Table 3.

Results From ROC Curve Analyses of Whether Villages Fall Below Thresholds of 25% Prevalence and 25 Mean EPG in Year 5 to Predict Prior Years, Means of Prior Years, or Changes in Prior Years

Prevalence
Year	Area Under the ROC Curve (%)	Threshold (%)	Sensitivity (95% CI)	Specificity (95% CI)
1	84.56	67.38	86.36 (78.41–93.18)	74.19 (62.90–83.91)
2	84.45	53.83	85.53 (77.63–92.14)	79.59 (67.35–89.80)
3	95.10	43.71	89.06 (81.25–95.31)	91.67 (80.56–100.00)
4	97.37	41.73	96.15 (90.38–100.00)	86.96 (73.91–100.00)
5	NA	25.00	NA	NA
Mean of 1 and 2	87.22	58.69	85.84 (81.93–89.46)	83.94 (78.76–89.12)
Mean of 1, 2, and 3	92.73	54.08	88.46 (84.23–91.92)	91.30 (86.09–95.65)
Change at 2 (from 1)	59.76	−16.83	44.88 (39.46–50.00)	76.68 (70.47–82.38)
Change at 3 (from 1)	78.40	−16.27	69.93 (64.86–75.34)	79.87 (73.38–86.36)
Intensity
Year	Area Under the ROC Curve (%)	Threshold (EPG)	Sensitivity (95% CI)	Specificity (95% CI)
1	86.38	113.43	92.00 (86.00–97.00)	70.00 (56.00–82.00)
2	82.46	67.91	88.10 (80.95–94.05)	70.73 (56.10–85.37)
3	90.03	64.67	91.67 (84.72–97.22)	75.00 (57.14–89.29)
4	86.65	37.26	91.07 (83.93–98.21)	84.21 (68.42–100.00)
5	NA	25.00	NA	NA
Mean of 1 and 2	84.40	71.00	84.62 (80.77–88.19)	73.29 (66.46–79.50)
Mean of 1, 2, and 3	86.00	104.11	94.64 (92.13–97.14)	68.42 (58.95–76.84)
Change at 2 (from 1)	59.54	−37.20	79.67 (75.27–83.79)	49.07 (40.99–56.52)
Change at 3 (from 1)	59.28	−72.39	89.02 (85.37–92.38)	47.54 (38.52–56.56)

The area under the ROC curve can be thought of as the expected percentage that a randomly drawn village below the year 5 threshold is less than a randomly drawn village that is above the threshold.

Abbreviations: CI, confidence interval; EPG, eggs per gram; NA, nonapplicable; ROC, receiving operating characteristic.