The Motor and Social Development scale (MSD) was developed by the National Center for Health Statistics to measure dimensions of the motor, social, and cognitive development of young children from birth through three years. The items were derived from standard measures of child development (Bayley Scales of Infant Development, the Gesell Scale, Denver Developmental Screening Test), which have high reliability and validity (Poe 1986). The scale was developed for use in the 1981 National Health Interview Survey (a large national health survey that included 2,714 children up to age four) and in the third National Health and Nutrition Examination Survey (NHANES, 1988-1994). Analyses by Child Trends, a non-profit, non-partisan research organization, of the scale in the 1981 Child Health Supplement to the National Health Interview Survey established the age ranges at which each item's developmental milestone is generally reached by U.S. children (Peterson and Moore 1987). The MSD scale has been used in the National Longitudinal Survey of Children and Youth (Statistics Canada) and by other smaller scale studies of child development such as the Boston Infant Follow-up Program.

Based on the child's age, NLSY79 mothers answer fifteen age-appropriate items out of 48 motor and social development items. These items have been used with a full spectrum of minority children with no apparent difficulty. Prior to 2002, a Spanish version of the scale was available to NLSY79 mothers whose principal language was Spanish.

Description of the MSD

The NLSY79 Motor and Social Development assessment has eight components (parts A through H) that a mother completes contingent on the child's age. Part A is appropriate for infants during the first four months of life (i.e., zero through three months) and the most advanced section, Part H, is addressed to children between the ages of 22 and 47 months. Each section contains 15 yes/no questions about whether the child has ever performed each age-appropriate behavior. For example, the mother of an infant less than 3 months of age is asked questions such as whether her child's eyes have ever followed a moving object from one side to the other, or smiled at someone when that person talked to or smiled at the child. A mother of a child aged 22-47 months is asked questions such as whether their child has ever walked up stairs (one foot on each step), or said his or her first and last name with no help.

Scoring the MSD

All of the MSD items are dichotomous (no=0, yes=1)). The total raw score for children of a particular age is obtained by summing all the "yes" responses in the age-appropriate section. No proration has been undertaken on this assessment since the proportion of missing items is modest and there was some question about the appropriateness of the procedure, given that later items in the assessment tend to be more difficult than earlier items, and hence non-response is not random across items.

Age eligibility for the MSD

In the 1986-2000 surveys, MSD scores were generated for children ages 0-3 years. In 2002 very young children were not administered assessments, which means that MSD scores were not generated for children under age 2 years in 2002. The MSD was not administered in 2004 due to budget constraints. From 2006 to 2016, mothers completed the MSD for children ages 0-3.

Norms for the MSD

Associated with each raw score is a series of norms: (1) an overall age-based percentile and standard score and (2) same-gender by age percentile and standard scores. That is, boys were scored using the male national norms and girls were assigned female national norms, and both genders received combined gender norm scores. Normed scores are provided in Appendix C in the NLSY79 Child/YA Codebook Supplement.

Normed scores were constructed by CHRR using data from the nationally representative sample in the 1981 Child Health Supplement to the National Health Interview Survey (National Center for Health Statistics 1984). Analyses by Child Trends (a non-profit, non-partisan research organization) of the scale in the 1981 Child Health Supplement to the National Health Interview Survey established the age ranges at which each item's developmental milestone is generally reached by U.S. children (Peterson and Moore 1987).

Completion rates for the MSD

The overall completion rate for the MSD assessment showed a decline through 1998 and then increased to higher levels once the Mother Supplement became a CAPI instrument in 2000. The overall completion rate for the current survey round can be found in Table 6 in the Child Assessments—Introduction section. A substantial proportion of the non-completions in pre-CAPI years resulted from situations where the mother skipped the section in the paper booklet or inadvertently left a number of the items blank.

Validity and reliability of the MSD

Readers interested in information about the validity and reliability of the NLSY79 Child data for this assessment may want to examine the discussions of the MSD in the NLSY79 Child Handbook: 1986-1990 and The NLSY Children, 1992: Description and Evaluation, both available on the Research/Technical Reports page. Analyses based on the NHANES III data indicate that low birth weight status and pre-term delivery are associated independently with small, but measurable, delays in MSD (Hediger et al., 2002).

Age, gender, and racial differences on the MSD

Caution should be exercised when interpreting results for three-year-olds, the oldest group completing this assessment. The Motor and Social Development assessment tends to "top out" for three-year-olds and does not provide a sensitive ceiling for these older children. For this reason, researchers using the assessment should include an age control in any multivariate analyses even when they are using normed scores. In general, the distribution of scores for NLSY79 children on this assessment tends to be more peaked for the youngest and oldest children (e.g., see Table 3.3 in the 2002 version of The NLSY79 Child Assessments: Selected Tables, available on the Research/Technical Reports page).

While not described in these tables, it is also useful to note reported gender differences at the youngest ages. Infant girls score significantly higher than their male counterparts, consistent with other evidence regarding early gender differences in motor and social development. Researchers interested in analyzing boys or girls separately are reminded that discrete gender-specific norms are available.

These items have been used with a full spectrum of minority children with no apparent difficulty.

MSD scores in the database

There are 5 summary scores for the MSD. In addition to the raw score, there are overall and gender-specific standard scores and percentile scores. 

Question names for the raw scores, overall scores, and same-gender normed scores for Motor & Social Development, from the final survey round, are listed in Table 1 in the Child Assessments—Introduction section.