Table 2—

Distribution characteristics and reliability estimates of the St George's Respiratory Questionnaire scales in the general population weighted sample

Observed range0–92.80–1000–79.70–83.4
% With worst possible score (floor)
%With best possible score (ceiling)41.243.559.521.1
% With missing data#
% With missing score1.
Cronbach's Alpha+
 Probable case of COPD0.770.900.890.95
 Nonprobable case of COPD0.730.840.870.91
Scale success rate %+
 Probable case of COPD81.384.492.388.0
 Nonprobable case of COPD87.571.994.286.0
  • n=862

  • COPD: chronic obstructive pulmonary disease

  • sd: standard deviation

  • COPD: chronic obstructive pulmonary disease

  • #: percentage of individuals with at least one missing item

  • : percentage of individuals with missing score after handling missing data recommended by authors was applied

  • +: calculated separately for probable and nonprobable cases of COPD by using Multitrait Analysis Program because it is not possible to apply weights with this package