TESTING SPHERICITY UNDER A MIXTURE MODEL

The robustness of Mauchly's sphericity test criterion when sampling from a mixture of two multivariate normal distributions is studied. The distribution of the sphericity test criterion when the sample covariance matrix has a non-central Wishart density of rank one is derived in terms of Meijer's G-functions; its distribution under the mixture model is then deduced. The robustness is studied by computing actual significance levels of the test under the mixture model using the critical values under the usual normal model.     

Evaluation of an educational intervention upon knowledge, attitudes, and behavior concerning drinking/drugged driving.

The Contra Costa County educational program for juveniles found guilty of driving under the influence (DUI) was evaluated. Over 600 juveniles convicted of DUI from 1983 to 1988 formed the study group for this research and of these over 100 participated in the educational program. Assessment of program participants was conducted for knowledge, attitudes and behavior. Participants demonstrated increased knowledge, stronger attitudes against driving under the influence, and less risky alcohol and automobile related behaviors. County juvenile records analyzed by the logit procedure showed that class participants had a significantly lower number of repeat offenses compared to non-program participants that could not be explained by race, offense severity, age or gender.     

Cognitive-behavioral-expressive interventions with aggressive and resistant youths.

Research into the nature of aggressive behavior in youths has demonstrated that these youths are often the victims of abuse, exhibit aggressive behavior in early childhood, and remain aggressive into young adulthood. The treatment approach described in this article is a modification of Monahan's [1981] model of the prediction of violent behavior and the anger-management approach of Novaco [1985], and integrates the developmental models of Piaget [1963] and Erikson [1959]. The program is a combination of cognitive, behavioral, and expressive therapies and is targeted to the reduction of dysfunctional cognitive, affective, behavioral, and problem-solving patterns of aggressive youths. As referrals of such aggressive clients are often involuntary, interventions with unwilling and resistant clients are also presented.     

Children's gender- and age-based categorization in similarity and induction tasks

The present studies examined children's and adults' preferences for gender- or age-based categorization using similarity and inductive inference tasks. Four-year-olds, 6-year-olds, and adults looked at pictures of people and decided which of two was more like a target (similarity condition) or which shared a novel age- or gender-related property with the target (inference condition). Age or gender-based matches were possible. The results are consistent with previous findings that gender-based classification decreases with age. However, they also demonstrate that children use gender more for judging similarity than for making inferences about novel properties. Distinct patterns emerge from the two tasks: 6-year-olds and adults in both conditions categorize more by age than gender; 4-year-olds categorize by gender more than age in the similarity task, but by age more in the induction task. Only adults differentiated by property in the inference condition. These findings suggest that the salience of gender categories cannot entirely be attributed to their inductive potential. Gender has a salience beyond what would be predicted by its power for directing novel generalizations.     

Estimation of noncentrality parameters

We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator.     

The Micro System of Deviance in Intimate Relationships*

Deviance in intimate relationships may lie as much within the micro system of such relationships as it does within the personalities of the actors involved. Using a Parsonsian framework, it is argued that the strain of systemically disequilibrated relationships can produce deviant personality adaptations which, in turn, intensify conflict and deviance in those relationships. It is also proposed that a reciprocal quality exists to such maladaptations, with each member of the dyad contributing to the amplification of a stable system of deviant behavior patterns within the relationship. Because the patterns of maladaptive dyads spill over into parent-child relationships, they have implications for understanding intergenerational transmission of deviance between intimates.     

ONE LUMP OR TWO: UNITARY VERSUS BIFURCATED MEASURES OF INJURY AT THE USITC

The most popular methodology used by the US International Trade Commission (USITC) commissioners to determine whether dumped and/or subsidized imports injure competing domestic industries has been rejected by reviewing bodies because it does not distinguish injury caused by unfairly traded imports from other demand or supply changes. We estimate injury to the domestic industry due to changes in unfairly traded import price and to other causes for 44 USITC dumping and/or subsidy investigations. Change in unfairly traded import price was typically not the most important cause of injury to the domestic industry. (JEL F13 )     

Effects of Medicaid managed care policies on mental health service use among a national probability sample of children in the child welfare system

Children in the child welfare system are dependent upon Medicaid to finance services for their considerable mental health needs. This study examines the effects of Medicaid policies on mental health service use among a national probability sample of children in the child welfare system. Data for this study came from the National Survey of Child and Adolescent Well-Being, the Caring for Children in Child Welfare study, and the Area Resource File. Weighted multivariate logistic regression analyses were conducted to estimate effects of policy variables on children's use of mental health services, controlling for child-level covariates and county-level health resources. Children in counties with behavioral carve-outs under Medicaid managed care had lower odds of inpatient mental health service use. Medicaid managed care enrollment and variations in type of provider reimbursement did not affect use of mental health services. Older age, greater need for mental health services, and higher levels of caregiver education were associated with increased odds of service use. Restrictions on use of inpatient mental healthcare caused by behavioral carve-outs may disproportionately affect children in the child welfare system who have high rates of such use. Careful adoption of carve-outs is necessary to assure appropriate care for these children.