Table 4

The sensitivity, specificity, PPV and Youden Indices for all possible cut-off scores for BDI, TQI, and all possible pairs of cut-off scores BDI and TQI to identify both workers who were diagnosed as having MDD and those who were not diagnosed as having MDD but had other psychiatric disorders frequently comorbid with MDD

	Sensitivity	Specificity	PPV	Youden Index
BDI cut-off score
4	62.0	61.6	43.9	0.237
5	58.6	65.0	44.7	0.236
6	51.7	73.3	48.3	0.250
7	44.8	80.0	52.0	0.248
8	41.3	86.6	60.0	0.280
9	41.3	90.0	66.6	0.313
10	37.9	91.6	68.7	0.295
11	31.0	93.3	69.2	0.243
12	27.5	96.6	80.0	0.242
13	27.5	98.3	88.8	0.259
14	24.1	98.3	87.5	0.224
15	24.1	98.3	87.5	0.224
16	17.2	98.3	83.3	0.155
17	13.7	98.3	80.0	0.121
18	10.3	98.3	75.0	0.086
TQI cut-off score
1	48.2	60.0	36.8	0.082
2	20.2	88.3	46.1	0.090

BDI	TQI	Sensitivity	Specificity	PPV	Youden Index
Pairs of cut-off scores
4	2	62.0	61.6	43.9	0.237
5	2	58.6	65.0	44.7	0.236
6	2	55.1	71.6	48.4	0.268
7	2	48.2	78.3	51.8	0.266
8	2	48.2	81.6	56.0	0.299
9	2	48.2	83.3	58.3	0.316
10	2	44.8	83.3	56.5	0.281
11	2	37.9	85.0	55.0	0.229
12	2	34.4	86.6	55.5	0.211
13	2	34.4	86.6	55.5	0.211
14	2	31.0	86.6	52.9	0.177
15	2	31.0	86.6	52.9	0.177
16	2	27.5	86.6	50.0	0.142
17	2	24.1	86.6	46.6	0.108
18	2	20.6	86.6	42.8	0.073
4	1	62.0	48.3	36.7	0.104
5	1	58.6	50.0	36.1	0.086
6	1	58.6	55.0	38.6	0.136
7	1	55.1	56.6	38.0	0.118
8	1	55.1	58.3	39.0	0.135
9	1	55.1	58.3	39.0	0.135
10	1	51.7	58.3	37.5	0.100
11	1	48.2	58.3	37.5	0.100
12	1	48.2	60.0	36.8	0.082
13	1	48.2	60.0	36.8	0.082
14	1	48.2	60.0	36.8	0.082
15	1	48.2	60.0	36.8	0.082
16	1	48.2	60.0	36.8	0.082
17	1	48.2	60.0	36.8	0.082
18	1	48.2	60.0	36.8	0.082

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