Adding meaning to measurement: Initial Rasch analysis of the ASHA FACS Social Communication Subtest

Background: The American Speech‐Language‐Hearing Association Functional Assessment of Communication Skills (ASHA FACS) has established validity and reliability for individuals with aphasia. However, subtest scores are summed and averaged across subtests, making it difficult to describe individuals' communication behaviours. Item‐response theory provides a methodology to assess the measurement properties of established assessments by transforming ordinal data into interval data, calibrated for both person ability measures and item difficulty on the same linear scale. The result is that behaviours can be ordered and described in ways that are more informative and useful than reporting raw scores. This study was funded by the VA Associated Health Rehabilitation Research Predoctoral Fellowship, the Office of Research and Development, Rehabilitation R&D Services, Department of Veterans Affairs and NIH NIDCD P50 Grant #DC003888‐04. We wish to acknowledge the support of Leslie Gonzalez Rothi, Director of the Bra...