Clinical utility of the category test as a multidimensional instrument

The construct and criterion validities of the Category Test (CT) were evaluated in 162 participants who had sustained traumatic brain injury and had been screened carefully for confounding factors. Maximum likelihood factor analysis identified 2 latent constructs, consistent with previous research. However, only subtests associated with the Proportional Reasoning factor (Subtexts V and VI) demonstrated consistent criterion validity in terms of sensitivity to injury severity. Performance of Subtext III, associated with the Spatial Positioning factor, was in the range of chance for more than a third of the sample, without any relationship to injury variables. It was concluded that the CT has construct validity as a multidimensional instrument but that only the Proportional Reasoning factor has criterion validity in the evaluation of sequelae of traumatic brain injury.