Cross-cultural adaptation of the Neck Disability Index and Copenhagen Neck Functional Disability Scale for patients with neck pain due to degenerative and discopathic disorders. Psychometric properties of the Polish versions

Table 3 Cronbach's alpha, criterion validity and test-retest reliability values for the NDI-PL and CDS-PL

		Test			Retest		Test-retest reliability
	Cronbach's alpha	Concurrent validity	Correlation between NDI-PL and CNFDS-PL	Cronbach's alpha	Concurrent validity	Correlation between NDI-PL and CNFDS-PL
NDI-PL	0.84	rs = 0.42 p < 0.001	0.87	0.85	rs = 0.40 p = 0.002	0.79	ICC = 0.87 95% CI from 0.80 to 0.92
CDS-PL	0.90	rs = 0.42 p < 0.001	p < 0.001	0.90	rs = 0.40 p = 0.001	p < 0.001	ICC = 0.93 95% CI from 0.89 to 0.95

NDI-PL- Polish language version of the Neck Disability Index
CDS-PL- Polish language version of the Copenhagen Neck Functional Disability Scale

ISSN: 1471-2474