Measuring Instruments
Data were collected by administering 9 questionnaires
to patients and family caregivers. All scales used have
previously demonstrated validity and reliability (internal
consistency), including establishing reference ranges for
correlation coefficients as derived from the Spearman rank
correlation in the manner of the London Chest Activity of
Daily Living Scale for use in patients with COPD12 and
validation by expert review in which the experts on a panel
specified their level of agreement to the stated items according to the method of Hyrka¨s et al. Modified scales were validated according to the method of Rubio et al, which calculates content validity index (CVI) by computing
the CVI for each item and dividing the number of
experts who rated the item above 3 points by the total
number of experts, which represents the proportion of experts who deemed each item as valid content; the instrument CVI was estimated by calculating the average CVI across items by the number of items.