Table 7.

Discriminatory ability of the velocity field diagram relative to the reference standard (TUG) tested among fallers (n = 280)

TUG
VFD	Test condition	Positive	Negative	Total	Estimated sensitivity of VFD	estimated specificity of VFD
	Positive	70	130	200	63.63%	23.53%
	negative	40	40	80
	Total	110	170	280

VFD Velocity diagram; VFD correctly identified 70 of the 110 positive samples, so the estimated sensitivity of VFD is 70/110 × 100% = 63.63%. Four of the 170 negative samples were correctly identified, so the estimated specificity of VFD is 40/170 × 100% = 23.53%.; McNemar test: Pa = 200/280 = 0.7143, Pb = 110/280 = 0.3929, Pa/Pb = 0.3214, p = 0490; odds ratio larger/smaller) = 3.25; 95% CI: 0.97—1.06