Abstract
Social-emotional functioning is foundational for children's healthy development and lifelong well-being. The NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox®) includes social-emotional measures for ages 3 and older, leaving a gap for assessing very young children. The new NIH Baby Toolbox directly addresses this measurement gap through its developmentally sensitive, tablet-based assessments of infant and toddler social-emotional functioning. This paper describes the domain conceptualization, measure selection, and psychometric evaluation of the Baby Toolbox Social-Emotional Functioning measures. Through an expert survey and literature review on conceptual frameworks, definitions, and existing measures, six subdomains were identified: Temperament, Negative Affect, Psychological Well-Being, Self-Regulation, Social Communication, and Social Relationships. Specific measures were selected from existing instruments/paradigms and adapted for iPad administration. They include the Infant, Early Childhood, and Childhood Behavior Questionnaire very short forms; the Patient Reported Outcome Measurement Information System (PROMIS®) Early Childhood Parent Report Anger/Irritability, Anxiety, Depressive Symptoms, Positive Affect, Flexibility, Frustration Tolerance, Child-Caregiver Interactions, and Peer Relationships; and the newly developed Social Observation Measure and Caregiver Checklist. Social-Emotional Functioning Measures were validated and normed with 2398 US children (n = 2021 English, n = 377 Spanish) aged 3-48 months using classical and modern test theory. Measures had moderate to high internal and test-retest reliability. Small to moderate intradomain correlations suggest each measure captured related, but unique, components; interdomain associations showed subdomains were distinct. Associations with existing measures supported construct validity. Overall, the Baby Toolbox Social-Emotional Functioning assessments provide reliable, valid, and nationally normed assessments for researchers and clinicians to evaluate infant and toddler social-emotional functioning in a practical and meaningful way.