§ Abstract
The relationship between neuropsychological test battery composition and underlying cognitive factor structures remains a fundamental question for understanding human cognitive architecture and optimizing assessment practices. This study examined whether empirically-derived factor structures vary systematically across different battery configurations and how these structural differences relate to general intelligence measurement. Using exploratory factor analysis with parallel analysis for factor retention, we analyzed cognitive factor structures across eight distinct neuropsychological test batteries containing 5-11 subtests each. The analysis processed 5,112,905 subtest scores from 757,427 participants who completed web-based cognitive assessments. Results revealed that seven of eight batteries exhibited unidimensional factor structures, with single factors explaining 22-27% of variance. Only the most comprehensive battery containing 11 subtests across multiple cognitive domains yielded a two-factor solution with moderate interfactor correlation. Split-sample validation demonstrated exceptional factor stability across all batteries. These findings challenge prevailing assumptions that increasing battery breadth necessarily produces more complex factor structures. The predominance of unidimensional structures across diverse battery compositions provides empirical support for the robustness of general intelligence measurement while informing evidence-based principles for neuropsychological test construction. These results underscore the importance of factor structure analysis as a standard practice in cognitive assessment validation and have significant implications for how intelligence test batteries are constructed and evaluated