The shortened disabilities of the arm, shoulder and hand questionnaire ( Quick DASH): validity and reliability based on responses within the full-length DASH

Table 4 Reliability

Scale	Test-retest reliability		Cross-sectional reliability				Agreement with DASH
	Baseline		Baseline		Follow-up		Baseline		Follow-up
	Agreement	Difference*					Agreement	Difference	Agreement	Difference
	ICC (95% CI)^†	mean (95% CI)	alpha	ITC range	alpha	ITC range	ICC (95% CI)^†	mean (95% CI)^‡	ICC (95% CI)^†	mean (95% CI)^‡
DASH	0.93 (0.86–0.97)	0.9 (- 2.3–4.0)^a	0.97	0.41–0.86	0.98	0.57–0.90	1	0	1	0
*Quick* DASH	0.93 (0.87–0.97)	-0.2(-3.6–3.1)^b	0.92	0.42–0.83	0.95	0.63–0.88	0.96 (0.84–0.98)	4.2 (3.2–5.3)	0.97 (0.92–0.99)	2.6 (1.7–3.4)
Random-11 1	0.92 (0.84–0.96)	-2.1(-5.7–1.5)^c	0.93	0.55–0.82	0.95	0.55–0.88	0.96 (0.92–0.98)	3.1 (2.0–4.2)	0.97 (0.91–0.98)	3.4 (2.4–4.5)
Random-11 2	0.93 (0.85–0.96)	-0.3(-3.7–3.1)^b	0.91	0.42–0.81	0.95	0.62–0.87	0.97 (0.96–0.98)	1.7 (0.7–2.7)	0.99 (0.98–0.99)	0.7 (0–1.4)

*calculated as the score at time 1 minus the score at time 2.
^†All ICC values were statistically significant (p < 0.001).
^‡All differences between the DASH and the other 3 forms were significant (p ≤ 0.001) except for random-11 form 2 at follow-up (p = 0.053)
^ap = 0.6, ^bp = 0.9, ^cp = 0.2.
ICC, intraclass correlation coefficient; alpha, Cronbach alpha coefficient; ITC, item-total correlation