Corrigendum to: Cross Validation of the Prodromal Questionnaire 16-Item Version in an Adolescent Help-Seeking Population

Corrigendum to “Cross Validation of the Prodromal Questionnaire 16-Item Version in an Adolescent Help-Seeking Population” by Yvonne de Jong et al. Schizophrenia Bulletin Open, Volume 1, Issue 1, January 2020, sgaa033, doi:10.1093/schizbullopen/sgaa033.

In this paper, all ROC analyses were performed using SPSS version 25.0. When performing ROC analyses, SPSS produces an output with cutoff values that are the averages of two consecutive ordered observed test values. When this paper first published, these cutoff values were not rounded up and the sensitivity and specificity scores in the same line were therefore given a lower cutoff score than they should have received. This article has now been corrected so that all cutoffs found and described have been increased with one point. The sensitivity and specificity scores in the tables and supplement have also been corrected accordingly (moving down one line). The conclusions of the article correspond to the previously stated conclusions. A cutoff of seven or more agreed items was chosen, but some text changes due to the altered screening values were necessary.

Table 2.

Screening Properties of the PQ-16, Comprehensive Assessment of At-Risk Mental States (CAARMS) Diagnosis of UHR or Psychotic Threshold vs No CAARMS Diagnosis, Using Method A

PQ-16 Cutoff	Sensitivity	Specificity	PPV	NPV	True Positives	True Negatives	False Positives	False Negatives
Total group, n = 325
5	0.97	0.18	46.2	89.7	132	35	154	4
6	0.93	0.25	47.1	82.5	126	47	142	10
7	0.85	0.42	51.3	79.8	116	79	110	20
8	0.77	0.55	55.3	77.0	105	104	85	31
9	0.65	0.69	60.5	73.6	89	131	58	47
10	0.51	0.81	65.7	69.5	69	153	36	67
Girls, n = 217
5	0.98	016	50.8	90.0	100	18	97	2
6	0.92	0.23	51.4	76.5	94	26	89	8
7	0.87	0.38	55.6	77.2	89	44	71	13
8	0.78	0.55	60.3	73.3	79	63	52	23
9	0.70	070	67.0	72.1	71	80	35	31
10	0.55	0.83	73.7	67.4	56	95	20	46
Boys, n = 108
5	0.94	0.23	36.0	89.5	32	17	57	2
6	0.94	0.28	37.7	91.3	32	21	53	2
7	0.79	0.47	40.9	83.3	27	35	39	7
8	0.77	0.55	44.1	83.7	26	41	33	8
9	0.53	0.69	43.9	76.1	18	51	23	16
10	0.38	0.78	44.8	73.4	13	58	16	21

Note: Bold values represent the selected cutoff. NPV, negative predictive values; PPV, positive predictive values; PQ-16, Prodromal Questionnaire 16-item version; UHR, ultra-high risk.

Table 3.

Comparison of Cutoff Scores With the Best Values in Scoring Methods B and C by Including Distress, per Gender and in the Total Group

PQ-16 Cutoff	Sensitivity	Specificity	PPV	NPV	True Positives	True Negatives	False Positives	False Negatives
Method B
Total group n = 324
5	.89	.37	50.2	82.4	120	70	119	15
6	.79	.47	51.4	75.9	107	88	101	28
7	.70	.62	56.6	74.1	94	117	72	41
8	.55	.73	59.7	69.5	74	139	50	61
Boys n = 108
4	.88	.32	37.5	85.7	30	24	50	4
5	.79	.42	38.6	81.6	27	31	43	7
6	.68	.54	40.4	78.4	23	40	34	11
7	.53	.66	41.9	75.4	18	49	25	16
Girls n = 216
5	.92	.34	55.0	83.0	93	39	76	8
6	.83	.42	55.6	73.8	84	48	67	17
7	.75	.59	61.8	73.1	76	68	47	25
8	.58	.73	65.6	66.7	59	84	31	42
Method C
Total group n = 324
7	.88	.38	50.4	81.8	119	72	117	16
8	.84	.45	52.3	80.2	114	85	104	21
9	.80	.54	55.7	79.2	108	103	86	27
10	.73	.59	56.0	75.2	98	112	77	37
Boys n = 108
7	.71	.43	36.4	76.2	24	32	42	10
8	.68	.46	36.5	75.6	23	34	40	11
9	.65	.57	40.7	77.8	22	42	32	12
10	.59	.63	42.6	77.0	20	47	27	14
Girls n = 216
7	.94	.35	55.9	87.0	95	40	75	6
8	.90	.44	58.7	83.6	91	51	64	10
9	.85	.53	61.4	80.3	86	61	54	15
10	.77	.56	60.9	73.9	78	65	50	23

Note: For more cutoffs and screening values see supplementary material. NPV, negative predictive values; PPV, positive predictive values; PQ-16, Prodromal Questionnaire 16-item version.