The theoretical and practical determination of clinical cut-offs for the British Sign Language versions of PHQ-9 and GAD-7

Table 3 PHQ-9 and GAD-7 cut-offs compared with PHQ-9 BSL and GAD-7 BSL cut-offs, indicating different statistical choices

English version (Cut-offs calculated on hearing population)
Cut-off choice [95 % bootstrap CI]		PHQ-9	GAD-7
Equalising	sens = spec	10	8
Equalising	sens, spec	88 %, 88 % [28]	77 %, 82 % [28]
BSL version (Cut-offs calculated on Deaf population)
Cut-off choice		PHQ-9 BSL	GAD-7 BSL
Maximising	Maximise sens + spec	10 [8.1, 13.2]	6 [5.1, 7.2]
	sens, spec	78 %, 95 %	91 %, 94 %
	Error	19.3 %	8.3 %
	LR+	16.5	15.3
Equalising	sens = spec	8 [6.5, 8.7]	6 [5.1, 7.2]
	sens, spec	86 %, 81 %	91 %, 94 %
	Error	14.5 %	8.3 %
	LR+	4.6	15.3
Prioritising treatment FN:FP = ~1:2	Cost function: false negative judged twice as bad as false positive	4 [2.1, 7.2]	3 [0.0, 3.9]
	sens, spec	96 %, 55 %	97 %, 67 %
	Error	10.8 %	7.8 %
	LR+	2.1	2.9

ISSN: 1471-244X