Evaluating fidelity to the wraparound service model for youth: application of item response theory to the Wraparound Fidelity Index.

The wraparound process is a mechanism for multisystem planning and care coordination for youth with serious emotional and behavioral problems. Fidelity monitoring is critical to effective implementation of evidence-based practices in children's mental health, as it helps ensure that complex interventions like wraparound are implemented as intended. The 40-item Wraparound Fidelity Index, Version 4 (WFI-4; Bruns, Burchard, Suter, Leverentz-Brady, & Force, 2004) is the most frequently used measure of fidelity to the wraparound process, but analysis of its psychometric properties is insufficient. An item response theory approach, Rasch partial credit models for ordered polytomous data, was used on ratings from 1,234 facilitators, 1,006 caregivers, and 221 team members, focused on 1,478 youths (55% male). Results indicated the WFI-4 measured a unidimensional construct, with little evidence of item bias and good item and model fit. However, the item information curve was skewed, with most people endorsing high-fidelity responses, and several items had duplicative location estimates. A reduced 20-item measure is proposed. Internal reliability estimates for scores from this reduced measure were approximately equivalent to the longer measure. However, both versions would benefit from additional items located in the highest fidelity area of either version of the scale where scores by greater than half of our sample fall, but only 3 items are located. PsycINFO Database Record (c) 2013 APA, all rights reserved.