Iowa State University

Janet Nieuwsma Melby

As the Director of the Observation Unit as ISBR, Janet Nieuwsma Melby oversees approximately 20 full and part-time staff members who specialize in behavioral assessments of children, adolescents, young adults, and parents as they engage in temperament, activity, or discussion tasks. More information about the work of the Observation Unit and the consultation services provided by the unit is available through the unit link on this website.

As a scientist at ISBR, Janet Nieuwsma Melby's research focuses on observational methodology, adolescent academic competence, and adolescent substance use. Data for this research are mainly from the Iowa Youth and Families Project, the Family Transitions Project, and the Family and Community Health Project. She also serves as an Adjunct Associate Professor of Human Development and Family Studies in the College of Human Sciences.

In the area of observational methodology, the Iowa Family Interaction Rating Scales (IFIRS), that she and others produced, provides a useful set of measures for studying social processes and individual development. With this system, trained observers supply valuable information on family processes and relationships, especially in areas that may be difficult for participants to assess objectively. In conjunction with self- and family- member-reports, observer ratings enable researchers to employ multi-informant techniques in testing hypotheses, thus reducing method-variance problems. Intraclass correlations (ICCs) for observer ratings range from .55 to .85 for the single scales used in most analyses. In general, ICCs are higher for composite measures than for single ratings. Structural equation modeling techniques also provide a useful framework for evaluating quality of observer and family-member assessments within a single analytic context.

Analyses using the IFIRS observational measures of martial hostility and relationship quality demonstrated acceptable internal consistency of items, substantial reliability for constructs, and support for the validity of observational measures. Assessments of marital warmth/prosocial behaviors supported the reliability of global ratings and illustrated that evaluations of validity must consider task context (discussion or problem solving). When observer ratings of adolescent behaviors were validated against self-, sibling-, and parent-reports of behaviors and evaluations of the relationship, age of sibling (younger or older than adolescent) and type of task context (parents present or absent) were important considerations. Acceptable inter-observer reliability, internal consistency and test/retest reliabilities have been obtained for composite measures of parental warmth, hostility and discipline. Preliminary results suggest the absence of systematic bias in ratings of Caucasian and African-American parent-child dyads by African-American and Caucasian observers, although some mean differences in ratings of hostility and warmth/support were observed.

In the area of academic competence, Melby's longitudinal analyses revealed that parenting practices actually foster changes in academic accomplishment across time. Setting and positively reinforcing appropriate behavioral standards (parent management) increased adolescents' academic performance, whereas hostility (negative emotional affect) decreased academic performance. Parental hostility also increased adolescents' problems at school, operating through their perception of being mistreated, thus supporting a social-contextual perspective.

Melby and colleagues also found support for a family investment model to explain the association between family of origin socioeconomic characteristics and youths' educational attainment in young adulthood. Initially assessed when youth were age 13 years, parents' educational level, occupational prestige, and family income each had a statistically significant direct relationship with youths' educational attainment at age 26 years. Parents' educational level and family income also demonstrated statistically significant indirect effects on later educational attainment through their associations with growth trajectories for supportive parenting, sibling relations, and adolescent academic engagement. Supportive parenting and sibling relations were linked to later educational attainment through their association with adolescent academic engagement. Academic engagement during adolescence was associated with educational attainment in young adulthood.

In the area of adolescent substance use, Melby and colleagues found adolescent males with tobacco-using peers and/or a sibling who used tobacco more likely to use tobacco concurrently and in the future. Harsh/inconsistent parenting was associated with higher adolescent males' tobacco use, whereas nurturant/involved parenting was associated with lower adolescent tobacco use. Most associations operated directly and all had indirect effects through peers.

Four patterns of substance use from 8th through 12th grades were identified in a series of analyses by Melby and Vargas. Abstainers showed no or low smoking or alcohol use; for this group, family factors were important and school performance higher. Increasers accelerated use over time with a sudden higher rate of consumption from 10th to 12th grades. Heavy users initiated early, had a high level of use, and increased use over time. Both increasers and heavy users exhibited lower school performance and parents who smoked and had alcohol problems. The fourth group, decreasers, showed heavy use during 8th through 10th grades and use declined by 12th grade. Decreasers and heavy users showed higher substance use among siblings and peers. In general, low tobacco and alcohol use were related to low or no parental or sibling use. Male gender, higher deviant values, lower school performance and friends and/or siblings who used tobacco characterized youth most at risk for tobacco involvement.

The work of the Observation Unit and Melby's scientific work are primarily supported by grants and subcontracts awarded to the Institute for Social and Behavioral Research and to the Partnership in Prevention Science Institute at Iowa State University.