The development and psychometric analysis of the short-form Pulmonary Functional Status Scale (PFSS-11)

This article describes the development and psychometric evaluation of the short-form Pulmonary Functional Status Scale (PFSS-11©) derived from the previously validated 35-item PFSS, using data from 179 subjects (120 Chronic Obstructive Pulmonary Disease [COPD]/59 normative, non-COPD). Items were extracted based on item-response distribution and commonality >.60. Factor analysis yielded a three-factor solution, accounting for 65.6% of total variance. Construct validity was supported by PFSS-11© scores for COPD versus norms (p < .001). The PFSS-11© was robustly associated with the PFSS-35 (r = .93), accounting for 88% of variance in the longer version. Internal consistency was satisfactory and significant response to treatment was shown by score changes pre/post-rehabilitation. The PFSS-11© has solid psychometric properties useful in research and clinical practice, similar to the PFSS-35.