Factor analytic and item response theory evaluation of the Penn State Worry Questionnaire in women with cancer
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- Wu, S.M., Schuler, T.A., Edwards, M.C. et al. Qual Life Res (2013) 22: 1441. doi:10.1007/s11136-012-0253-0
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Cancer survivors frequently experience worry about a variety of topics, including fear of recurrence. However, general measures of worry still require examination of reliability for this vulnerable population. This study utilized modern psychometric methods to examine the reliability of a worry measure in women with breast or gynecologic cancer.
Women with cancer (n = 332) completed the 16-item Penn State Worry Questionnaire (PSWQ), which has an abbreviated 8-item version (PSWQ-A). Categorical confirmatory factor analysis (CCFA) was used to determine the factor structure and item response theory (IRT) was used to examine score reliability.
CCFA supported a two-factor structure with 11 positively worded items and the 5 negatively worded items loading on different factors. IRT analysis of the 11 positively worded items showed that each was contributing meaningful information to the overall scores. The 11 positively worded items and the PSWQ-A produced the most reliable scores for levels of worry ranging from one θ below to two θ above the mean.
The 11 positively worded items of the PSWQ and the 8-item PSWQ-A were suitable for use in cancer patients while the full PSWQ was unsuitable due to inclusion of the negatively worded items. Future research should consider measuring worry when examining distress in cancer survivors.