Modeling distances between humans using Taylor’s law and geometric probability

Taylor’s law states that the variance of the distribution of distance between two randomly chosen individuals is a power function of the mean distance. It applies to the distances between two randomly chosen points in various geometric shapes, subject to a few conditions. In Réunion Island and metropolitan France, at some spatial scales, the empirical frequency distributions of inter-individual distances are predicted accurately by the theoretical frequency distributions of inter-point distances in models of geometric probability under a uniform distribution of points. When these models fail to predict the empirical frequency distributions of inter-individual distances, they provide baselines against which to highlight the spatial distribution of population concentrations.     

Operationalizing the Construct of Friendship among Children: A Psychometric Comparison of Sociometric-Based Definitional Methodologies

Peer relations researchers generally agree that friendship involves a close, mutual, dyadic relationship. However, the lack of consensus on how to operationalize this construct has limited our understanding of the role of friendship in social adjustment. The present study directly compared the psychometric properties (i.e., number of friendships identified, concordances, and stability) of the five major different definitions of friendship used in the literature. Fourth- and fifth-grade students (N = 90) completed a battery of sociometric measures at two different times separated by eight weeks. Friendship dyads were then identified using the following definitional criteria: (1) mutual positive nominations; (2) mutal high ratings (i.e., 4 or 5 on a five-point Likert-type scale); (3) one positive nomination reciprocated by a rating of 5; (4) one positive nomination and mutual high ratings; and (5) one positive nomination and mutual ratings averaging at least 4. Frequency and concordance analyses indicated differences across the five definitions. In addition, the friendships identified by each of the five definitions were similarly moderate in their stability. Explanations for, and the possible implications of, these differences are discussed.     

Semiparametric estimation of employment duration models

There are a variety of economic areas, such as studies of employment duration and of the durability of capital goods, in which data on important variables typically are censored. The standard techinques for estimating a model from censored data require the distributions of unobservable random components of the model to be specified a priori up to a finite set of parameters, and misspecification of these distributions usually leads to inconsistent parameter estimates. However, economic theory rarely gives guidance about distributions and the standard estimation techniques do not provide convenient methods for identifying distributions from censored data. Recently, several distribution-free or semiparametric methods for estimating censored regression models have been developed. This paper presents the results of using two such methods to estimate a model of employment duration. The paper reports the operating characteristics of the semiparametric estimators and compares the semiparametric estimates with those obtained from a standard parametric model.     

Evaluation of treatment programs for persons with severe mental illness: moderator and mediator effects

This study evaluated several statistical models for estimating treatment effects in a randomized, longitudinal experiment comparing assertive community treatment (ACT) versus brokered case management (BCM). In addition, mediator and moderator analyses were conducted. The ACT clients had improved outcomes in terms of housing and psychiatric symptoms than BCM clients. Case management housing assistance and financial assistance partially mediated housing outcomes. No reliable mediators were found for psychiatric symptoms, and no reliable moderators were found for either housing or psychiatric symptoms. The study also made several important methodological advances in the analysis of longitudinal data in randomized experiments.     

OUT OF UTOPIA:

An important segment of writings on postindustrialization is distinctly utopian in stressing the greater mastery and control made possible by recent innovations in information technology. The utopian theme underscores the technical outcomes of innovations and highlights their benefits for ameliorating social problems. By contrast, our work suggests that many of the social problems in contemporary society are a consequence of recent innovations in information technology. We argue that postindustrial theorists are correct in stressing mastery over certain technical problems but incorrect in slighting the destabilizing effect innovations have on organizations and the markets in which these organizations participate. These destabilizing effects complicate organizational strategies by increasing market risk and uncertainty. Since most organizations are risk aversive, social problems are created as organizations externalize their costs and pass along risk to other, more dependent actors. Illustrations from two institutions, politics and the economy, indicate that many postindustrial innovations are associated with heightened competition as well as greater risk and uncertainty across the institutional order. We conclude that postindustrial technology introduces no net gain in man aging the complexities of the social world. Risk and control are both integral to technological innovation and constitute the paradox of postindustrialization.     

Nonverbal intimacy,sex, and compliance: A field study

The present study was designed to explore further the effects of nonverbal behaviors and sex on compliance. Male and female subjects who had just found a dime in a phone booth were approached by a male or female experimenter and were asked to return the dime that the experimenter had supposedly just lost. In the Eye Contact condition, the experimenter gazed at the subject as the request was made, whereas in the No-Eye Contact condition he/she did not. In addition, the experimenter lightly touched half of the subjects while making his/her request, but did not touch the other half. Replicating previous findings, it was found that both eye contact (significantly) and touching (marginally) produced increased rates of compliance. Extending prior results, these effects were obtained for male experimenters. Furthermore, a Sex of experimenter times Sex of subject interaction effect was obtained, such that subjects were much more willing to comply with the request of an opposite, rather than same sex experimenter. Questionnaire data suggested that: 1) subjects were aware of the touch, but not of the eye contact variable, and 2) the requesters were perceived as much more attractive when they were of the opposite, rather than the same sex as the subjects.     

Semiparametric Estimation of a Proportional Hazard Model with Unobserved Heterogeneity

The proportional hazard model with unobserved heterogeneity gives the hazard function of a random variable conditional on covariates and a second random variable representing unobserved heterogeneity. This paper shows how to estimate the baseline hazard function and the distribution of the unobserved heterogeneity nonparametrically. The baseline hazard function and heterogeneity distribution are assumed to satisfy smoothness conditions but are not assumed to belong to known, finite-dimensional, parametric families. Existing estimators assume that the baseline hazard function or heterogeneity distribution belongs to a known parametric family. Thus, the estimators presented here are more general than existing ones.     

Contract Length as Risk Management When Labor is not Homogeneous

This paper examines the choice of contract length for workers who possess unique skills. Uncertainty, facing both the worker and the firm, creates an incentive to reallocate risk. The uncertainty arises from two sources: variation in the market value of the worker's human capital and fluctuation in the worker's physical production. Long‐term contracts are typically modeled as compensating wage differentials, or as a solution to the problem of asymmetric information. This paper develops a model proposing more complex behavior in the reallocation of risk between the contracting parties. The model shows that long‐term labor contracts are most likely to be observed when price uncertainty in the labor market exceeds the worker's productive uncertainty.