Table 3

The sensitivity, specificity, PPV and Youden Indices for all possible cut-off scores for BDI, TQI and all possible pairs of cut-off scores of BDI and TQI to identify workers who were diagnosed with major depressive disorder

	Sensitivity	Specificity	PPV	Youden Index
BDI cut-off score
4	100	56.4	9.7	0.564
5	100	60.0	10.5	0.600
6	75.0	67.0	9.6	0.420
7	75.0	74.1	12.0	0.491
8	75.0	80.0	15.0	0.550
9	75.0	82.3	16.6	0.573
10	75.0	84.7	18.7	0.597
11	50.0	87.0	15.3	0.370
12	50.0	90.5	20.0	0.405
13	50.0	91.7	22.2	0.417
14	50.0	92.9	25.0	0.429
15	50.0	92.9	25.0	0.429
16	25.0	94.1	16.6	0.191
17	25.0	95.2	20.0	0.202
18	0	98.8	25.0	0.214
TQI cut-off score
1	100	60.0	10.5	0.600
2	75.0	88.2	23.0	0.632

BDI	TQI	Sensitivity	Specificity	PPV	Youden Index
Pairs of cut-off scores
4	2	100	56.4	9.7	0.564
5	2	100	60.0	10.5	0.600
6	2	100	65.8	12.1	0.658
7	2	100	72.9	14.8	0.729
8	2	100	75.2	16.0	0.752
9	2	100	76.4	16.6	0.764
10	2	100	77.6	17.3	0.776
11	2	75.0	80.0	15.0	0.550
12	2	75.0	82.3	16.6	0.573
13	2	75.0	82.3	16.6	0.573
14	2	75.0	83.5	17.6	0.585
15	2	75.0	83.5	17.6	0.585
16	2	75.0	84.7	18.7	0.597
17	2	75.0	85.8	20.0	0.608
18	2	75.0	87.0	21.4	0.620
4	1	100	47.0	8.1	0.470
5	1	100	49.4	8.5	0.491
6	1	100	52.9	9.0	0.529
7	1	100	55.2	9.5	0.552
8	1	100	56.4	9.7	0.564
9	1	100	56.4	9.7	0.564
10	1	100	56.4	10.0	0.576
11	1	100	57.6	10.0	0.576
12	1	100	57.6	10.5	0.600
13	1	100	60.0	10.5	0.600
14	1	100	60.0	10.5	0.600
15	1	100	60.0	10.5	0.600
16	1	100	60.0	10.5	0.600
17	1	100	60.0	10.5	0.600
18	1	100	60.0	10.5	0.600

BDI, Beck Depression Inventory; PPV, positive predictive value; TQI, two-question case-finding instrument.