ImPACT is the most commonly utilized computerized neurocognitive assessment for the clinical management of sport concussion. The cognitive composite scores that ImPACT currently reports include Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, and Impulse Control. However, exploratory factor analytic studies report that two or more factors may better represent ImPACT’s latent structure, suggesting that the current cognitive composites may not adequately represent the cognitive constructs ImPACT assesses. The latent structure of ImPACT cognitive baseline scores was examined using exploratory (EFA) and confirmatory factor analysis (CFA) of valid baseline ImPACT scores for 36,091 high school athletes. These athletes were randomly divided into two samples. The first sample was a calibration sample used for EFA and the second sample was a cross-validation sample used for CFA to estimate the best model identified in the calibration phase, along with other models that were reported in the literature or based on theoretical considerations, including hierarchical and bifactor models. EFA identified a first-order four-factor solution consisting of Visual Memory, Visual Reaction Time, Verbal Memory, and Working Memory constructs. CFA indicated that this four-factor model provided superior fit for the data, while the current five-composite structure of ImPACT provided a poor fit for the data. The latent constructs identified in this study using CFA do not map well onto the composite scores that are currently used to interpret ImPACT performance. Future research should investigate whether interpretation of ImPACT based on the constructs identified here will be more useful for clinical decision making than current approaches. (PsycInfo Database Record (c) 2021 APA, all rights reserved).