• Development of an Instrument to Measure the Appraisal of Cancer-related Fatigue

      Clark, Jane C.; Department of Biochemistry and Molecular Biology (2001-05)
      Based on a conceptual definition and model of fatigue, a three-phase descriptive study was conducted to develop items for a self-report instrument to measure the appraisal of fatigue. In Phase I, interviews with people experiencing cancer-related fatigue and a review of the literature were used to generate items to sample four constructs of the appraisal of fatigue: Fatigue, meaning, impact, and adaptability to fatigue. In Phase II, items were refined and reduced based on recommendations of a panel of content experts (N=7), instrument development expert, and pilot study results (N=20). In Phase III, reliability and validity estimates of the Fatigue Appraisal Scale were evaluated based on responses of a heterogeneous sample (N=196) of individuals diagnosed with cancer. Acceptable estimates of internal consistency reliability (Cronbach’s alpha) were determined for subscales of Fatigue (a =.91), Impact of Fatigue (a =.89), and Adaptability to Fatigue (a =.74). The internal consistency reliability of the Meaning of Fatigue subscale did not meet the required .60 for a new measurement instrument. To assess construct validity, hypotheses were generated and tested about the relationships of the subscales of the Fatigue Appraisal Scale and selected subscales of the Profile of Mood States-Shortened Form, Fatigue Assessment Instrument, and Functional Assessment of Cancer Therapy-Anemia. Results indicated low to moderate correlations (r = .20 to .70) among the subscales in the directions hypothesized with the exception of the correlation of the Adaptability to Fatigue subscale and the FACT-An Emotional and Functional Well-being subscales and the Impact of Fatigue subscale and the POMS Tension-anxiety subscale. Construct validity was examined further through factor analysis, using principal components analysis with varimax rotation. A four-factor solution with item loadings of .40 or greater on each factor was determined. Four items did not load on any of the four factors and were deleted. The factors were named: Global Fatigue, Impact of Fatigue, Adaptability to Fatigue, and Challenge of Fatigue. Items from the original Meaning of Fatigue subscale loaded on the Global Fatigue, Impact of Fatigue subscale or on the new factor, Challenge of Fatigue. Findings supported the factor structure for the instrument. Recommendations for future validation studies of the 34-item Revised Fatigue Appraisal Scale were offered.