Development and validation of the NIH Baby Toolbox® Math measures.

The NIH Baby Toolbox® Math measures were designed to assess early mathematical abilities in infants and toddlers, providing a standardized approach to evaluating foundational mathematics competencies among other developmental trajectories. This manuscript describes the development of these measures as well as the reliability and validity of these measures in a diverse sample of children aged 1-42 months. More than 2500 participants were recruited from various socio-economic backgrounds and geographic locations to ensure a representative sample. The validation process involved a multi-method approach, including correlations with age, test-retest reliability, and external validity against two popular developmental assessments. Results from N = 926 participants (714 English-exposed, 212 Spanish-exposed) indicated strong correlation with age for all but one of the measures and good test-retest reliability. Additionally, significant correlations were found between the NIH Baby Toolbox Math measures and established early childhood assessments (ASQ-3 and Bayley-4), confirming known-groups validity. These findings suggest that the Baby Toolbox Math measures are reliable and valid tools for assessing early mathematical skills in infants and toddlers, with potential applications in both research and clinical settings. Future research should explore longitudinal outcomes and the impact of early interventions on mathematical development.