Measuring executive function in preschoolers: Is a single assessment occasion sufficient?

This study examines whether a single assessment occasion is sufficient to measure executive function (EF) in preschoolers. We administered a battery of EF tasks to 283 children aged 3-5 years (54% female) from diverse racial and ethnic backgrounds (41% non-Hispanic white, 36% non-Hispanic black, 14% Hispanic, 8% mixed race, 1% Asian, 1% American Indian) across three occasions within an academic year. Using longitudinal bifactor models, we decomposed task performance into trait and state components. Results indicated that most of the reliable variation in EF task scores reflected trait-level influences (consistency estimates = 50%-89%). By contrast, most of the reliable variation in comparison task scores (simple reaction time task; assessor-rated attention during testing) reflected state-level influences (consistency estimates = 32%-36%). This is the first study to characterize the relative proportion of state- and trait-level influences on EF tasks in preschool-aged children. Our study underscores the importance of considering both trait and state influences in EF measurement and provides recommendations for future research. (PsycInfo Database Record (c) 2026 APA, all rights reserved).