Development of short forms from the PROMIS™ sleep disturbance and Sleep-Related Impairment item banks

Abstract

This article reports on the development of short forms from the Patient-Reported Outcomes Measurement Information System (PROMIS™) Sleep Disturbance (SD) and Sleep-Related Impairment (SRI) item banks. Results from post-hoc computerized adaptive testing (CAT) simulations, item discrimination parameters, item means, and clinical judgments were used to select the best-performing 8 items for SD and SRI. The final 8-item short forms provided less test information than the corresponding full banks, but correlated strongly with the longer forms. The short forms had greater measurement precision than the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS), as indicated by larger test information values across the continuum of severity, despite having fewer total items--a major advantage for both research and clinical settings.

Figures

Figure 1. Correlations between full-scale or fixed short form and CAT for Sleep Disturbances

Figure 2. Correlations between full-scale or fixed short form and CAT for Sleep-related Impairment item bank

Figure 3. Test Information Curves for the PROMIS Sleep Disturbance Full Item Bank, Short Form, Epworth Sleepiness Scale (ESS), and Pittsburgh Sleep Quality Index (PSQI)

Note: The test information of 10 derived from IRT on the left-side y-axis is roughly equivalent to the reliability of .90 derived from CTT on the right-side y-axis. Therefore, the curves above the horizontal line (test information of 10 to reliability of .90) indicate the section on the theta scale has reliability of .90 or above.

Figure 4. Test Information Curves for the PROMIS Sleep-Related Impairment Full Item Bank, Short Form, Epworth Sleepiness Scale (ESS), and Pittsburgh Sleep Quality Index (PSQI)

Note: The test information of 10 derived from IRT on the left-side y-axis is roughly equivalent to the reliability of .90 derived from CTT on the right-side y-axis. Therefore, the curves above the horizontal line (test information of 10 to reliability of .90) indicate the section on the theta scale has reliability of .90 or above.