Objective: This article provides the results of the psychometric testing of the Brief Impairment Scale (BIS). The BIS is a 23-item instrument that evaluates three domains of functioning: interpersonal relations, school/work functioning, and self-care/self-fulfillment. It capitalizes on the strengths of existing global measures while addressing some of their limitations.
Method: Cross-sectional parent respondent data from one clinical (N = 757) and two community samples (N = 1,888 and 1,132) of children ranging in age from 4 to 17 years is employed to test the reliability and validity of the BIS. Receiver operating characteristic analyses are employed to assess useful cutoff scores on the scale.
Results: The total scale's internal consistency ranged from 0.81 to 0.88 and from 0.56 to 0.81 on the three subscales. Test-retest reliability for individual items ranged from fair to substantial in all but six items. The BIS has high convergent and concurrent validity. Receiver operator characteristic analyses suggest possible thresholds for different uses.
Conclusions: The BIS is psychometrically sound, useful in assessments and as an outcome measure in clinical practice and research. Its advantages over other global impairment instruments are that it is respondent based, short in administration time, and multidimensional.