Parent and Sibling Influences on the Quality of Children's Conflict Behaviours across the Preschool Period

Parent and sibling influences on children's development of conflict management strategies were examined. Data consist of naturally occurring, in‐home sibling disputes of 37 families at two time points. The siblings were approximately two and four years old at Time 1, and four and six years old at Time 2. Parents' and children's use of conflict strategies that reflect proactive autonomy assertions such as opposition and verbal and physical power were the focus of the current study. Results suggest that parents and siblings play an important role in shaping children's conflict behaviours over time. For instance, parents' reliance on unelaborated opposition to the child, and older siblings' increased use of physical power predicted decreases in younger siblings' ability to assert themselves during conflict. In addition, increased proportions of opposition from a younger sibling was associated with the older siblings using less verbal aggression and using more mature conflict strategies such as justifying their own behaviour to their younger sibling. As sibling conflict is a salient child rearing concern for parents, practical implications are discussed.     

Inequalities for linear combinations of gamma random variables

We study the behavior of the tail probabilities of weighted averages of certain independently and identically distributed random variables as the weights are varied. We show that the upper and lower tails are smallest when all the weights are equal. Our results apply to exponential, chi-squared, gamma, and Weibull random variables.     

USE OF EXPERT RATINGS AS SAMPLING STRATA FOR A MORE COST-EFFECTIVE PROBABILITY SAMPLE OF A RARE POPULATION

We consider situations in which externally observable characteristics allow experts to quickly categorize individual households as likely or unlikely to contain a member of a rare target population. This classification can form the basis of disproportionate stratified sampling such that households classified as "unlikely" are sampled at a lower rate than those classified as "likely," thereby reducing screening costs. Design weights account for this approach and allow unbiased estimates for the target population.We demonstrate that with sensitivity and specificity of expert classification at least 70%, and ideally at least 80%, our approach can economically increase effective sample size for a rare population. We develop heuristics for implementing this approach and demonstrate that sensitivity drives design effects and screening costs whereas specificity only drives the latter. We demonstrate that the potential gains from this approach increase as the target population becomes rarer. We further show that for most applications, unlikely strata should be sampled at 1/6 to ? the rate of likely strata.This approach was applied to a survey of Cambodian immigrants in which the 82% of households rated "unlikely" were sampled at ? the rate as "likely" households, reducing screening from 9.4 to 4.0 approaches per complete. Sensitivity and specificity were 86% and 91% respectively. Weighted estimation had a design effect of 1.26 so screening costs per effective sample size were reduced 47%. We also note that in this instance, expert classification appeared to be uncorrelated with survey outcomes of interest among eligibles.     

Efficiency of lattice conditional independence models for multinormal samples with non-monotone missing data

For multivariate normal data with non-monotone (i.e. arbitrary) missing data patterns, lattice conditional independence (LCI) models determined by the observed data patterns can be used to obtain closed-form MLEs (Andersson and Perlman, 1991, 1993). In this paper, three procedures — LCI models, the EM algorithm, and the complete-data method — are compared by means of a Monte Carlo experiment. When the LCI model is accepted by the LR test, the LCI estimate is more efficient than those based on the EM algorithm and the complete-data method. When the LCI model is not accepted, the LCI estimate may lose efficiency but still may be more efficient than the EM estimate if the observed data is sparse. When the LCI model appears too restrictive, it may be possible to obtain a less restrictive LCI model by.discarding only a small portion of the incomplete observations. LCI models appear to be especially useful when the observed data is sparse, even in cases where the suitability of the LCI model is uncertain.     

The role of reversals in order‐restricted inference

A statistical model is said to be an order‐restricted statistical model when its parameter takes its values in a closed convex cone C of the Euclidean space. In recent years, order‐restricted likelihood ratio tests and maximum likelihood estimators have been criticized on the grounds that they may violate a cone order monotonicity (COM) property, and hence reverse the cone order induced by C. The authors argue here that these reversals occur only in the case that C is an obtuse cone, and that in this case COM is an inappropriate requirement for likelihood‐based estimates and tests. They conclude that these procedures thus remain perfectly reasonable procedures for order‐restricted inference.     

Differential parenting and children's social understanding

In the current study, a curvilinear association was examined between differential parenting and children's social understanding as measured using standardized assessments and behavioral observations. Social understanding was comprised of theory‐of‐mind and behavior indicating understanding of others’ minds (i.e., cognitive sensitivity and internal state talk and reasoning during sibling interactions). Data came from a community sample of 372 children (51.6% males; M age = 5.57, SD = 0.77), their younger siblings (M age = 3.14, SD = 0.27), and their mothers who were observed in their homes. We hypothesized that in families with higher levels of differential parenting, both favored and disfavored older siblings would display poorer social understanding, but that disfavored children would be more negatively impacted. Results from a hierarchical regression analysis indicated an inverse linear effect, rather than a curvilinear relationship, between being favored by mother and siblings’ social understanding. Specifically, disfavored older children showed higher levels of social understanding when interacting with their favored younger sibling. This relationship remained significant after controlling for variables such as age, SES, and language. Findings suggest that differential parenting plays a role in children's ability to understand others.