The role of measuring functional impairment holds an important place in research, clinical practice, and service provision for children and adolescents. Responding to the growing need to measure serious emotional disturbances at the local, state, and national level, the Columbia Impairment Scale (CIS) was developed in the early 1990s and has remained one of the several popular scales for assessing functional impairment. However, despite the growing popularity of the instrument in research and practice, only a few studies to date have specifically examined the psychometric properties of the CIS. In this article, we describe the results of the first item response theory analysis of the CIS utilizing nationally representative data from the Medical Expenditure Panel Survey (N = 69,966). The results of our analysis lend support to the essential unidimensionality of the CIS and demonstrate that the scale is most reliable for those who exhibit high levels of functional impairment. Given the psychometric properties of the scale identified by our analysis, we contend that the CIS is a viable measure in the ongoing efforts to establish a national epidemiologic surveillance system to track the prevalence and impact of serious emotional disturbances in children and adolescents.
Keywords: Columbia Impairment Scale; behavioral health; functional impairment; item response theory; psychometrics.