Table 3. Classification statistics for alopecia areata.

	n positive	Sensitivity	Specificity	PPV	NPV
		Estimates (95% confidence intervals)
Algorithm
1	65	88.1 (77.1, 95.1)	92.8 (88.0, 96.1)	80.0 (68.2, 88.9)	96.0 (91.9, 98.4)
2	62	86.4 (75.0, 94.0)	93.9 (89.3, 96.9)	82.3 (70.5, 90.8)	95.5 (91.3, 98.0)
3	33	49.2 (35.9, 62.5)	97.8 (94.4, 99.4)	87.9 (71.8, 96.6)	85.4 (79.9, 90.0)
4	41	50.8 (37.5, 64.1)	93.9 (89.3, 96.9)	73.2 (57.1, 85.8)	85.4 (79.6, 90.0)
5	84	89.8 (79.2, 96.2)	82.8 (76.5, 88.0)	63.1 (51.9, 73.4)	96.1 (91.8, 98.6)
6	79	88.1 (77.1, 95.1)	85.0 (78.9, 89.9)	65.8 (54.3, 76.1)	95.6 (91.2, 98.2)
7	63	86.4 (75.0, 94.0)	93.3 (88.6, 96.5)	81.0 (69.1, 89.8)	95.5 (91.2, 98.0)
8	58	76.3 (63.4, 86.4)	92.8 (88.0, 96.1)	77.6 (64.7, 87.5)	92.3 (87.4, 95.7)
9	64	83.1 (71.0, 91.6)	91.7 (86.6, 95.3)	76.6 (64.3, 86.2)	94.3 (89.7, 97.2)