Statistical models for the analysis of controlled trials on acute migraine

Specific efficacy criteria were defined by the International Headache Society for controlled clinical trials on acute migraine. They are derived from the pain profile and the timing of rescue medication intake. We present a methodology to improve the analysis of such trials. Instead of analysing each endpoint separately, we model the joint distribution and derive success rates in any criteria as predictions. We use cumulative regression models for each response at a time and a multivariate normal copula to model the dependence between responses. Parameters are estimated using maximum likelihood. Benefits of the method include a reduction in the number of tests performed and an increase in their power. The method is well suited to dose–response trials from which predictions can be used to select doses and optimize the design of subsequent trials. More generally, our method permits a very flexible modelling of longitudinal series of ordinal data. Copyright © 2003 John Wiley & Sons, Ltd.     

地方立法主体扩容后对立法重复的重新审视

《立法法》修改后,地方立法主体急剧扩容,地方立法重复现象猛增。在新形势下,地方立法重复不应只包括了对上位法内容的重复,对同类地方性法规内容的重复也应归属于其范畴。这样一来,对地方立法重复的宽容度相应地应有所提升。故而,辩证地看待地方立法重复至关重要。地方立法重复虽然备受诟病,但却无法避免。对地方立法重复进行限制或是宽容,实质上应取决于立法主体的主观态度。地方立法重复以立法主体的主观态度为标准可分为两类,即惰性的地方立法重复和积极的地方立法重复。为有效规制地方立法重复,应该防止惰性的地方立法重复、包容积极的地方立法重复。     

Identifying Children's Peer Social Networks in School Classrooms: Links Between Peer Reports and Observed Interactions

Links between peer reports of social cluster membership and observed classroom interactions were examined in a sample of 72 children in 4^th grade and 7^th grade. All participating children in each classroom identified as many social clusters in the classroom as they could recall. Using the social‐cognitive map (SCM) procedure, these individual reports were aggregated to summarize the number of times a given child was nominated as being in the same social cluster as each of his or her classmates (i.e., a co‐nomination profile) and to identify the classmates in each child's social cluster. Extensive classroom observations allowed for a parallel summary of the number of times a given child was observed to interact with each of his or her classmates (i.e., an interaction profile). Results indicated that correlations between conomination profiles and interaction profiles were positive and statistically reliable. Children were observed to interact with members of their SCM‐identified social cluster at a rate four times higher than with other same‐sex classmates. These effects did not vary reliably by grade, sex or aggressive risk status.     

Sexual Behavior in Dutch and Belgian Children as Observed by Their Mothers

Abstract

Mothers' observations (N = 670) of child sexual behavior have been collected using an adapted version of the Child Sexual Behavior Inventory as developed by Friedrich et al. (1991). The ages of the boys (N = 351) and girls (N = 319) observed range from 0 to 11 years. The results show that there is a lot of variance in the frequency with which specific sexual behaviors are observed. The occurrence of specific behaviors varies with age. While some behaviors are observed more frequently as the child gets older, others are observed less frequently. Boys and girls only differ in a few behaviors. The finding that the behavioral items form an internally consistent scale suggests that there is a general tendency to show sexually related behaviors, which is more or less strongly present in children, which might be a precursor of differential levels of sexual desires in adults.     

Maximum likelihood estimation of sensitive proportion using repeated randomized response techniques

Randomized response techniques are designed to obtain usable data on sensitive issues while protecting the privacy of individuals. In this paper, based on repeating the randomized response technique, a new technique called repeated randomized response is introduced to increase the protection of privacy and efficiency of estimator for proportion of sensitive attribute. By using this technique, the proportion of academic cheating is estimated among students of Shahid Chamran University of Ahvaz, Ahvaz, Iran.     

Parameter estimation by contrast minimization for noisy observations of a diffusion process

We consider the estimation of unknown parameters in the drift and diffusion coefficients of a one-dimensional ergodic diffusion X when the observation Y is a discrete sampling of X with an additive noise, at times i δ, i=1,?…?, N. Assuming that the sampling interval tends to 0 while the total length-time interval tends to infinity, we prove limit theorems for functionals associated with the observations, based on local means of the sample. We apply these results to obtain a contrast function. The associated minimum contrast estimators are shown to be consistent. Some examples are discussed with numerical simulations.     

Comparisons of Performance and Job Insecurity in Union and Nonunion Sites of a Manufacturing Company

Layoffs and employment changes caused by current economic conditions have significant effects on employee work behavior and emotions as well as organizational outcomes. We examined the relationships between measures of job insecurity, organizational commitment, turnover, absenteeism, and worker performance within a manufacturer in Chapter 11 bankruptcy. A positive relationship was found between job insecurity and intentions to turnover, and a small negative correlation was found between measures of job insecurity and organizational commitment. Unobtrusive observations of union and nonunion performance over 4 months showed that nonunion production workers were on-task more frequently, although on-task behavior was high for both. Productivity and quality measures of different factories favored nonunion locations. Although comparisons between sites were constrained by a quasi-experimental design, repeated behavioral and outcome measures within sites showed differential effects when the company announced a plant closing in another state. Job insecurity appeared to be an establishing operation that produced differential effects between union and nonunion sites as well as among individual employees within sites.     

Interpolation,outliers mid inverse autocorrelations

The paper addresses the problem of estimating missing observations in an infinite realization of a linear, possibly nonstationary, stochastic processes when the model is known. The general case of any possible distribution of missing observations in the time series is considered, and analytical expressions for the optimal estimators and their associated mean squared errors are obtained. These expressions involve solely the elements of the inverse or dual autocorrelation function of the series.

This optimal estimator -the conditional expectation of the missing observations given the available ones- is equal to the estimator that results from filling the missing values in the series with arbitrary numbers, treating these numbers as additive outliers, and removing with intervention analysis the outlier effects from the invented numbers.     

A corrected likelihood ratio statistic for the multivariate regression model with antedependent errors

This paper addresses the problem of inference for the antedependence model (Gabriel, 1961, 1962). Antedependence can be formulated as an autoregressive process of general order which is non-stationary in time. Its primary application is in the analysis of repeated measurements data, that is, data consisting of independent replicates of relatively short time series. Our focus is on testing a general linear hypothesis in the context of a multivariate regression model with multivariate normal antedependent errors. Although the relevant likelihood ratio statistic was first presented by Gabriel (1961), the distribution of this statistics has not yet been derived. We present this derivation and show how this result leads to a simple correction factor to improve the x² approximation of the likelihood ratio statistic.