Factor analysis of the Revised Piper Fatigue Scale in a caregiver sample.

The Revised Piper Fatigue Scale (R-PFS) is an instrument designed to measure subjective fatigue that was developed in samples with physical illness. Its psychometric properties in nonclinical samples are unknown. The purpose of this study was to examine the psychometric properties of the R-PFS in a sample of caregivers of stroke survivors. The convenience sample of 132 caregivers was primarily women (74%), White (71%), college-educated (73%), and employed (52%), with a mean age of 56.7 years (SD = 13.71). Internal consistency reliabilities for the four R-PFS subscales and the total scale were excellent, ranging from .90 to .97. Principal axis factor analysis with oblique rotation was conducted to examine construct validity of the R-PFS. A three-factor solution explained 75.9% of the common variance. Two factors totally replicated the behavioral/severity and affective meaning subscales of the R-PFS. The third factor incorporated a combination of Piper's sensory and cognitive/mood subscales and appeared to summarize how fatigue makes the caregiver feel. The R-PFS demonstrated strong internal consistency reliability and construct validity in this sample. However, data suggest that caregivers may perceive certain feelings associated with fatigue as conceptually similar when these feelings are conceptually distinct in Piper's breast cancer sample. The study supports the need for psychometric evaluation of instruments developed in clinical populations prior to their use in nonclinical populations.