Table 4. Sensitivity and Specificity of the Insomnia Severity Index (n = 101)
ScoreSensitivitySpecificityFPR (n = 67)FNR (n = 34)Correctly Classified (n = 101)PPVNPV
110010.489.6 (60)0.0 (0)40.6 (41)36.2 (34/94)100 (7/7)
210016.483.6 (56)0.0 (0)44.6 (45)37.8 (34/90)100 (11/11)
310019.480.6 (54)0.0 (0)46.5 (47)38.6 (34/88)100 (13/13)
410022.477.6 (52)0.0 (0)48.5 (49)39.5 (34/86)100 (15/15)
510029.970.2 (47)0.0 (0)53.5 (54)42.0 (34/81)100 (20/20)
610035.864.2 (43)0.0 (0)57.4 (58)44.2 (34/77)100 (24/24)
710041.858.2 (39)0.0 (0)61.4 (62)46.6 (34/73)100 (28/28)
810052.247.8 (32)0.0 (0)68.3 (69)51.5 (34/66)100 (35/35)
997.161.238.8 (26)2.9 (1)73.3 (74)55.9 (33/59)97.6 (41/42)
1097.164.235.8 (24)2.9 (1)75.3 (76)57.9 (33/57)97.7 (43/44)
1194.168.731.3 (21)5.9 (2)77.2 (78)60.4 (32/53)95.8 (46/48)
1291.273.126.9% (18)8.8 (3)79.2 (80)63.3 (31/49)94.2 (49/52)
1385.376.123.9 (16)14.7 (5)79.2 (80)64.4 (29/45)91.1 (51/56)
1482.4 (28/34)82.1 (55)17.9 (12)17.6 (6)82.2 (83)70.0 (28/40)90.2 (55/61)
1576.582.117.9 (12)23.5 (8)80.2 (81)68.4 (26/38)87.3 (55/63)
1664.783.616.4 (11)35.3 (12)77.2 (78)66.7 (22/33)82.4 (56/68)
1752.986.613.4 (9)47.1 (16)75.3 (76)66.7 (18/27)78.4 (58/74)
1841.291.09.0 (6)58.8 (20)74.3 (75)70.0 (14/20)75.3 (61/81)
1935.392.57.5 (5)64.7 (22)73.3 (74)70.6 (12/17)73.8 (62/84)
2026.594.06.0 (4)73.5 (25)71.3 (72)69.2 (9/13)71.6 (63/68)
2117.697.03.0 (2)82.4 (28)70.3 (71)75.0 (6/8)69.9 (65/93)
235.91000.0 (0)94.1 (32)68.3 (69)100 (2/2)67.7 (67/99)
260.01000.0 (0)100 (34)66.3 (67)66.3 (67)
  • Data are %, % (n), or % (n/N).

  • FNR, false negative rate; FPR, false positive rate; NPV, negative predictive value; PPV, positive predictive value.