The Communicative Participation Item Bank (CPIB): item bank calibration and development of a disorder-generic short form

Abstract

Purpose: The purpose of this study was to calibrate the items for the Communicative Participation Item Bank (CPIB; Baylor, Yorkston, Eadie, Miller, & Amtmann, 2009; Yorkston et al., 2008) using item response theory (IRT). One overriding objective was to examine whether the IRT item parameters would be consistent across different diagnostic groups, thereby allowing creation of a disorder-generic instrument. The intended outcomes were the final item bank and a short form ready for clinical and research applications.

Method: Self-report data were collected from 701 individuals representing 4 diagnoses: multiple sclerosis, Parkinson's disease, amyotrophic lateral sclerosis, and head and neck cancer. Participants completed the CPIB and additional self-report questionnaires. CPIB data were analyzed using the IRT graded response model.

Results: The initial set of 94 candidate CPIB items were reduced to an item bank of 46 items demonstrating unidimensionality, local independence, good item fit, and good measurement precision. Differential item functioning analyses detected no meaningful differences across diagnostic groups. A 10-item, disorder-generic short form was generated.

Conclusions: The CPIB provides speech-language pathologists with a unidimensional, self-report outcomes measurement instrument dedicated to the construct of communicative participation. This instrument may be useful to clinicians and researchers wanting to implement measures of communicative participation in their work.

Keywords: assessment; communicative participation; dysarthria; item response theory; outcomes; outcomes measurement; voice disorders.

Figures

Figure 1

This is the test information function for the final item set of 46 items in the CPIB item bank. The solid line is the information function and the dotted line is the standard error curve.

Figure 2

This is the test information function for the 10-item General Short Form of the CPIB. Note that the overall shape of the function is similar to that for the full 46-item set although the amount of information in the short form (y axis) is lower because there are fewer items.