Experimental designs with dependent observations: New results and comments on previous results

We present a new sufficient condition on the covariance matrix of the normality distributed observations of an ANOVA model (with orthogonal decomposition of the total sum of squares) under which the F-statictics are distributed proportionally to Fisher F-random variables variables. A new proof of a previous result, a necessary and sufficient condition for applicability of Barlett’s test to the observations of a one-way ANOVA models, and comments on recent results are also given.     

A Stochastic Volatility Model With Conditional Skewness

We develop a discrete-time affine stochastic volatility model with time-varying conditional skewness (SVS). Importantly, we disentangle the dynamics of conditional volatility and conditional skewness in a coherent way. Our approach allows current asset returns to be asymmetric conditional on current factors and past information, which we term contemporaneous asymmetry. Conditional skewness is an explicit combination of the conditional leverage effect and contemporaneous asymmetry. We derive analytical formulas for various return moments that are used for generalized method of moments (GMM) estimation. Applying our approach to S&P500 index daily returns and option data, we show that one- and two-factor SVS models provide a better fit for both the historical and the risk-neutral distribution of returns, compared to existing affine generalized autoregressive conditional heteroscedasticity (GARCH), and stochastic volatility with jumps (SVJ) models. Our results are not due to an overparameterization of the model: the one-factor SVS models have the same number of parameters as their one-factor GARCH competitors and less than the SVJ benchmark.     

Bayesian modeling of university first-year students' grades after placement test

University first-year students grades are naturally correlated with the scores obtained at placement tests. Often this characteristic leads the university grades in the first exams to be asymmetrically distributed. Motivated by the analysis of grades of the basic Statistics examination of first-year students, we discuss informative priors for the shape parameter of the skew-normal model, a class of distribution which account for several degree of asymmetry. Our proposed prior leads to closed-form full-conditional posterior distributions, particularly useful in Markov Chain Monte Carlo simulation. A Gibbs sampling algorithm is discussed for the joint vector of parameters and the method is applied to a real data set from the School of Economics, University of Padua, Italy. Our analysis reveals that the correlation between the placement test and the grades of first-year students leads to a measurable positive skewness of the distribution of the university grades.     

Aggression in delinquent adolescents versus controls: the role of parental rearing

The role of social factors in the aetiology of aggression is still very unclear. To examine the interrelations between aggression and parental rearing factors, 133 delinquent adolescents and 108 same-aged schoolchildren from north western Russia were studied by means of the Aggression Questionnaire and the own memories of parental rearing questionnaire on parental rearing. Delinquent adolescents significantly differed from non-delinquents on aggression scores, as well as on parental rearing factors. Furthermore, the aggression scores in both groups under investigation were related with rejecting rearing practices. Our results point to the aetiological significance of parental rearing in the development of aggression among adolescents.     

Multisystemic Therapy for Child Abuse and Neglect: Do Parents Show Improvement in Parental Mental Health Problems and Parental Stress?

Multisystemic Therapy for Child Abuse and Neglect (MST-CAN) is an evidence-based program for families with children who experience maltreatment. This clinical trial is the first evaluation of MST-CAN in a German-speaking area. Parental psychological problems and parental stress have been shown to be risk factors for child abuse and neglect. By the end of treatment, parents reported significantly less psychological distress than before the start of MST-CAN. Six months after treatment, this reduction was still evident. However, parents did not report any significant reduction of parental stress at any of the three time points. MST-CAN is an effective intervention for child maltreatment that not only combats child abuse and neglect but also has the potential to alleviate parental psychological distress.     

COVID Health Structure Index: The Vulnerability of Brazilian Microregions

Social Indicators Research - Many developing countries have highly unequal health systems across their regions. The pandemic of COVID-19 brought an additional challenge, as hospital structures...     

SEARCH INTENSITY,DIRECTED SEARCH,AND THE WAGE DISTRIBUTION

We propose a search equilibrium model in which homogeneous firms post wages along with a vacancy to attract job seekers while homogeneous unemployed workers invest in costly job seeking. The key innovation relies on the organization of the search market and the search behavior of the job seekers. The search market is continuously segmented by wage level, individuals can spread their search investment over the different submarkets, and search intensity has marginal decreasing returns in each submarket. We demonstrate the existence of a nondegenerate equilibrium wage distribution. The density of this wage distribution is increasing at low wages and decreasing at high wages. The distribution can be right‐tailed, and, under additional restrictions, is hump‐shaped. Our results are illustrated by an example generating a Beta wage distribution.     

Index of Authors Volume 51

Authors Index

Index of Authors Volume 51