SIGNIFICANCE: In this study, we applied Many-Facets analysis, on the basis of Item Response Theory, to detect the differences of the report pattern between individuals with traumatic brain injury (TBI) and their informants on the Behavior Rating Inventory of Executive Function—Adult version (BRIEF–A). Although executive function deficit is one of the most common problems following TBI, how to accurately assess individuals’ executive function is still inconclusive. Because many of the laboratory-based tests have not established their ecological validity, subjective reports such as questionnaires used to assess patients’ executive function in the real-world environment reflect a more accurate status of their daily obstacles. Several factors, however, affect the congruency of reports on questionnaires in the TBI population. Researchers have argued that due to lack of self-awareness, self-reports from individuals with TBI might underestimate their own deficits. However, informant reports might be affected by factors such as expectation, caregiver burden, and emotional adjustment. The discrepancy of reports also depends on the domains of the outcome. For example, studies showed that self- and informant reports are more congruent on physical deficits than on cognitive impairments. Additionally, self- and informant reports showed higher agreement on specific questions than genetic questions. In 2009, Draper compared the subjective report of individuals with TBI and their close others and found strong agreement in their reports on the NeuroBehavioural Functional Inventory; however, Draper did not include instruments to assess everyday executive function. Although the BRIEF–A was developed to assess executive function in the real-world environment and can be completed by individuals or their informants, no study has compared self- and informant reports in the TBI population. Our research question is as follows: What are the differences between self- and informant reports on the BRIEF–A in a TBI sample?

METHOD: This is a cross-sectional survey study. Patients completed the surveys in person; informants completed the survey in person or by mail. Ninety individuals with moderate-to-severe TBI in outpatient rehabilitation or at least 1 yr postinjury and 89 caregivers were recruited from three sites. The BRIEF–A, using 3-point rating categories, consists of two indexes with 75 items: Behavioral Regulation Index (BRI) and Metacognition Index (MI). We conducted the Many-Facets Rasch Model to compare the reports between self and informants. This analysis can examine the response patterns between self and their informants, account for erratic responses, and identify the differences on item level.

RESULTS: The fixed chi-square values were statistically significant (p < .0001) for both the BRI and MI domains. The results indicate significant differences of the reports on domain level: BRI and MI. On the item level, informants reported more problems on four BRI items and one MI item. Patients reported more problems on one BRI item and one MI item.

CONCLUSION: In contrast to Draper’s findings, our participants rated themselves as having fewer deficits on executive function than their informants on both BRI and MI domains. However, this pattern did not exist across all the items. Our findings cannot be generated to the mild TBI population. Clinicians need to interpret the reports with caution, especially for the items that show discrepancy between self- and informant reports.