Abstract
BACKGROUND: Recently, the National Institutes of Health Roadmap for Medical Research initiative led a large-scale effort to develop the Patient-Reported Outcomes Measurement Information System (PROMIS). PROMIS's main goal was to develop a set of item banks and computerized adaptive tests for the clinical research community. Asthma, as the most common chronic childhood disease, was chosen for a disease-specific pediatric item bank. OBJECTIVES: The primary objective of this research is to present the details of the psychometric analyses of the asthma domain items. METHODS: Item response theory (IRT) analyses were conducted on a 34-asthma item bank. Test forms containing PROMIS Pediatric Asthma domain items were completed by 622 children ages 8 to 12. Items were subsequently evaluated for local dependence, scale dimensionality, and differential item functioning. RESULTS: A 17-item pool and an 8-item short form for the new PROMIS Pediatric Asthma Impact Scale (PAIS) were generated using IRT. The recommended 8-item short form contains the item set that provides the maximum test information at the mean (50) on the T-score metric. If more score precision is required, the complete 17-item pool is recommended and may be used in toto or as the basis of a computerized adaptive test (CAT). A shorter test form can also be created and scored on the same scale. CONCLUSIONS: The present study presents the PROMIS Pediatric Asthma Impact Scale (PAIS) developed with IRT, and provides the initial calibration data for the items.