Assessment of everyday problems with executive functioning following acquired brain injury (ABI) is greatly valued by neurorehabilitation services. Reliance on self-report measures alone is problematic within this client group who may experience difficulties with awareness and memory. The construct validity and reliability of independent ratings (i.e., ratings provided by a carer/relative) on the Dysexecutive Questionnaire (DEX-I) was explored in this study. Consistent with the results recently reported on the self-rated version of the DEX (DEX-S; Simblett & Bateman, 2011 ), Rasch analysis completed on 271 responses to the DEX-I revealed that the scale did not fit the Rasch model and did not meet the assumption of unidimensionality, that is, a single underlying construct could not be found for the DEX-I that would allow development of an interval-level measure as a whole. Subscales, based on theoretical conceptualisations of executive functioning (Stuss, 2007 ) previously suggested for the DEX-S, were able to demonstrate fit to the Rasch model and unidimensionality. Reliability of independent responses to these subscales in comparison to self-reported ratings is discussed. These results contribute to a greater understanding of how assessment of executive functioning can be improved.