Among infants and preschool age children, assessing cognitive and motor development in relation to specific developmental milestones is useful in understanding a child’s “developmental status” and whether the child appears to have developmental delay(s) in one or more realms. For instance, a child who is not walking by the age of 2 or not speaking simple sentences by the age of 3 may be delayed in this sphere of development compared to the majority of children of similar age. Three studies examined young homeless children on this dimension. Two of the studies, Wood et al. (1990) in Los Angeles, and Bassuk and Rosenberg (1990) in Boston used the Denver Developmental Screening Test (DDST), whereas the third study, Garcia Coll, Buckner, Brooks, Weinreb, and Bassuk (1998), which involved the infant and toddler cohort from the Worcester study, used the Bayley Scales of Infant Development (“Bayley”). As the name implies, the DDST is an easy-to-use screening instrument for identifying developmental delays in children. The Bayley is the gold standard measure of developmental status in infants and young children and requires specialized training to administer. The DDST is a set of questions asked of a parent or guardian about the child (usually with the child present), whereas the Bayley is administered by a trained tester via direct observation and interaction with the child.
Both the Los Angeles and Boston studies found that homeless preschool children were experiencing a greater proportion of developmental delays than the comparison groups of poor housed children. In the Wood et al. (1990) study, 15 percent of homeless children were found to have one developmental delay and 9 percent had two or more. These rates are significantly higher than that found in the general child population.10 The most common type of delay was in language. Bassuk and Rosenberg (1990) found much higher rates of developmental delay in their Boston study, with 54 percent of homeless children evidencing at least one delay versus 16 percent for children in the housed comparison group. Developmental tasks in the areas of language and social behavior were the two areas in which homeless children were having the most difficulty. In contrast to these two studies, Garcia Coll et al. (1998) found no differences between homeless and low-income housed infants/toddler’s developmental status on the Bayley. In fact, homeless children looked slightly better on both the mental and motor development subscales of this instrument (scores of 105 in both realms vs. about 101 for the housed comparison group). Moreover, scores on the Vineland Screener (a measure of adaptive behavior that asks a parent about a child’s communication, daily living, socialization, and motor skills) were almost identical. These low-income infant and toddlers’ scores were in the low-normal to normal range based on normative data for this instrument.