Analysis of the Pediatric Outcomes Data Collection Instrument (PODCI) in Ambulatory Children with Cerebral Palsy Using Confirmatory Factor Analysis and Item Response Theory Methods

摘要

BackgroundTraditional use of the Pediatrics Outcomes Data Collection Instrument (PODCI) assumes that all items have the same structure, are measuring the intended constructs, and assess the right levels of function to show change following orthopedic or neurologic intervention. Item response theory (IRT) methods can statistically account for inherent differences in PODCI item characteristics and thus reveal attributes of the measure important to effectiveness research. Our study uses IRT methods to determine whether PODCI items: fit the projected dimensional structure of the PODCI, assess function on each dimension at the right level for a population of ambulatory children with cerebral palsy (CP), and reveal changes following intervention in this population.