A genetic framework was developed for the interpretation of statistical parameters estimated from a diallel experiment among a fixed set of lines. These included average direct genetic, average maternal genetic, general combining ability, reciprocal, and line and specific direct and maternal heterotic effects. The genetic model is based on direct and maternal additive and dominance genetic effects as would be expected in animal species. The model assumes that dominance is the underlying basis of heterosis. As an example, litter size at birth was analyzed from a 5 × 5 diallel cross with mice.

Data from the 2007 National Survey of Children's Health are used to develop an index of positive child well-being that has several innovative and important characteristics. It distinguishes child well-being from contexts of child development; it is built with rich micro-data (rather than population-level macro-data) to create unique measures of well-being for individual children; and it focuses on positive, rather than negative, aspects of development. These data can be aggregated to provide a perspective on the proportions of children in the population who are doing well on all, some, or no developmental domains. Based on child development theory and research, the index is constructed within a framework of four conceptually distinct developmental domains, each of which is comprised of three sub-domains. The index distinguishes among children in predicted directions, by poverty level and parental education. White children tend to do better than Hispanic or black children in all domains, though neither minority subgroup is consistently better or worse off than the other subgroup. Girls score slightly higher than boys on the index. About three in four children score positively on three or four domains. The index provides a composite, multidimensional view of positive child well-being that can be useful to researchers and policy analysts, and which addresses some weaknesses of other similar indices.

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OVERVIEW Numerous studies have found links between the quality of the parents' relationship and positive outcomes for children and families. 1 Yet very little research has examined whether this association holds across various population subgroups, especially among disadvantaged groups. 2 Is the quality of the parents' relationship really associated with outcomes for children of low-income couples? For ethnic minority couples? For unmarried couples?To address this issue, Child Trends analyzed data from the 2007 National Survey of Children's Health. Analyses focus on more than 64,000 respondents 3 whose children were between the ages of six and 17.Results indicate that the parents' relationship quality is very consistently and positively associated with a range of child and family outcomes, including: child behavior problems (externalizing), child social competence, child school engagement, child internalizing (depression), parent-child communication, and parental feelings of aggravation. This association holds across varied subgroups, including: white, black and Hispanic couples; married and cohabiting couples; lower and higher income families; boys and girls, teens and younger children, immigrants and non-immigrants; and parents with postsecondary education, a high school education, and less than a high school education. In addition, the association holds in all but one comparison when social and economic differences are taken into account.