Patient-reported outcomes measurement information system (PROMIS) domain names and definitions revisions: further evaluation of content validity in IRT-derived item banks

Content validity of patient-reported outcomes (PROs) is evaluated primarily during item development, but subsequent psychometric analyses, particularly for item response theory (IRT)-derived scales, often result in considerable item pruning and potential loss of content. After selecting items for the PROMIS banks based on psychometric and content considerations, we invited external content expert reviews of the degree to which the initial domain names and definitions represented the calibrated item bank content. A minimum of four content experts reviewed each item bank and recommended a domain name and definition based on item content. Domain names and definitions then were revealed to the experts who rated how well these names and definitions fit the bank content and provided recommendations for definition revisions. These reviews indicated that the PROMIS domain names and definitions remained generally representative of bank content following item pruning, but modifications to two domain names and minor to moderate revisions of all domain definitions were needed to optimize fit with the item bank content. This reevaluation of domain names and definitions following psychometric item pruning, although not previously documented in the literature, appears to be an important procedure for refining conceptual frameworks and further supporting content validity.