This methodology report documents the design, development, and psychometric characteristics of the assessment instruments used in the second wave of the ECLS-B. The assessment instruments discussed measure children's cognitive development (BSF-R), socioemotional functioning (Two Bags Task), security of attachment (TAS-45), and physical development (height, weight, middle upper arm circumference (MUAC), and head circumference). The report also includes information about interviewer observations of the child and the child's environment, as well as indirect assessments of the children through questions in the parent interview.
