Table 2

Validity of acoustic analysis v stethoscope

A Convergent validity: acoustic analysis v stethoscope
	Wheeze			Rattles			Crackles
	Yes	No	Total	Yes	No	Total	Yes	No	Total
Yes	38	27	65	45	35	80	21	24	45
No	18	17	35	8	12	20	6	49	55
Total	56	44	100	53	47	100	27	73	100
	κ = 0.07 (−0.13 to 0.26)			κ = 0.11 (−0.05 to 0.27)			κ = 0.36 (0.18 to 0.54)

B Discriminant validity: stethoscope
	Wheeze v rattles			Wheeze v crackles			Rattles v crackles
	Yes	No	Total	Yes	No	Total	Yes	No	Total
Yes	30	26	56	12	42	54	8	44	52
No	22	22	44	15	31	46	19	29	48
Total	52	48	100	27	73	100	27	73	100
	κ = 0.01 (−0.18 to 0.21)			κ = −0.1 (−0.27 to 0.07)			κ = −0.24 (−0.4 to 0.07)

C Discriminant validity: acoustic analysis
	Wheeze v rattles			Wheeze v crackles			Rattles v crackles
	Yes	No	Total	Yes	No	Total	Yes	No	Total
2×2 tables demonstrating convergent and discriminant validity; κ (95% confidence interval) given for each comparison.
Yes	55	10	65	27	38	65	32	50	82
No	24	11	35	15	20	35	10	8	18
Total	79	21	100	42	58	100	42	58	100
	κ = 0.16 (−0.02 to 0.33)			κ = −0.03 (−0.19 to 0.16)			κ = −0.13 (−0.2 to 0.05)