Some characterizations of discrete distributions based on weak records

Let X ₁, X ₂,... be iid random variables (rv's) with the support on nonnegative integers and let (W _n , n≥0) denote the corresponding sequence of weak record values. We obtain new characterization of geometric and some other discrete distributions based on different forms of partial independence of rv's W _n and W _n+r —W _n for some fixed n≥0 and r≥1. We also prove that rv's W ₀ and W _n+1 —W _n have identical distribution if and only if (iff) the underlying distribution is geometric.     

Reconsidering union wage effects: Surveying new evidence on an old topic

I examine evidence on private sector union wage gaps in the United States. The consensus opinion among labor economists of an average union premium of roughly 15 percent is called into question. Two forms of measurement error bias downward standard wage gap estimates. Match bias results from Census earnings imputation procedures that do not include union status as a match criterion. Downward bias is roughly equal to the proportion of workers with imputed earnings, currently about 30 percent. Misclassification of union status causes additional attenuation in union gap measures. This bias has worsened as private sector density has declined, since an increasing proportion of workers designated as union are instead nonunion workers. Corrections for misclassification and match bias lead to estimated union gaps substantially higher than standard estimates, but with less of a downward trend since the mid 1980s. Private sector union gaps corrected for these biases are estimated from the CPS for 1973–2001. The uncorrected estimate for 2001 is .13 log points. Correction for match bias increases the gap to .18 log points; further correction for misclassification bias, based on an assumed 2 percent error rate, increases the gap to .24. Reexamination of the skill-upgrading hypothesis leads to the conclusion that higher union gap estimates are plausible. The conventional wisdom of a 15 percent union wage premium warrants reexamination.     

The Effect of Support Expectations on Prenatal Attachment: An Evidence-Based Approach for Intervention in an Adolescent Population

This study was designed to determine the significant variables predicting prenatal attachment in an adolescent population. Scientifically supported knowledge of the factors enhancing attachment plays a crucial role in assisting social workers and other health care professionals to accurately assess and intervene to decrease pregnancy risks. Previous prenatal attachment studies demonstrated conflicting findings due to problems from using different theoretical frameworks and research methodologies. In order to ensure consistency, this study infused an attachment theory perspective. Bowlby’s attachment theory, Levitt’s support expectations model, and research from prenatal relationship studies were integrated. The social survey sampled 129 minority status pregnant adolescents attending public school. Measurements included the Prenatal Attachment Inventory (PAI) and the Support Expectations Index (SEI). Regression analyses revealed that support expectation was a powerful predictor of prenatal attachment with pregnancy planning and less stress adding importantly to explain over 33% of the variance. Support expectation was a greater predictor of prenatal attachment than the actual support available. Findings also supported the construct of prenatal attachment as the initial stage of development of the life cycle. Janis B. Feldman is an Assistant Professor, University, of Texas-Pan American.     

Persisting Differences or Adaptation to German Fertility Patterns? First and Second Birth Behavior of the 1.5 and Second Generation Turkish Migrants in Germany

In this study, we use data of the German Mikrozensus to explore first and second birth behavior of migrants’ descendants. Whereas prior waves of the Mikrozensus only included respondents’ citizenship, in the survey years 2005 and 2009 also parental citizenship has been surveyed. This allows us to identify respondents’ migrant backgrounds, even if they have German citizenship. We distinguish those who migrated as children (1.5 generation) from those who were born to Turkish parents in Germany (second generation migrants). We compare both migrant generations to German non-migrants. Using discrete-time hazard models, our results show that 1.5 generation migrants have the highest probability of having a first and second birth, while German non-migrants have the lowest birth probabilities. The second generation lies in-between. This pattern also persists after taking the educational attainment of respondents into consideration. However, there seems to be an adaptation of highly educated second generation Turkish migrants to non-migrant Germans: we find no significant differences in the probability of having a first birth in the two groups. For second births, we do not find this pattern which might be related to the young age structure in the sample of second generation migrants.     

Optimum mixture designs in a restricted region

In a mixture experiment, the response depends on the proportions of the mixing components. Canonical models of different degrees and also other models have been suggested to represent the mean response. Optimum designs for estimation of the parameters of the models have been investigated by different authors. In most cases, the optimum design includes the vertex points of the simplex as support points of the design, which are not mixture combinations in the true non-trivial sense. In this paper, optimum designs have been obtained when the experimental region is an ellipsoidal subspace of the entire factor space which does not cover the vertex points of the simplex.     

Eliciting decision weights by adapting de Finetti’s betting-odds method to prospect theory

This paper extends de Finetti’s betting-odds method for assessing subjective beliefs to ambiguous events. Thus, a tractable manner for measuring decision weights under ambiguity is obtained. De Finetti’s method is so transparent that decision makers can evaluate the relevant tradeoffs in complex situations. The resulting data can easily be analyzed, using nonparametric techniques. Our extension is implemented in an experiment on predicting next-day’s performance of the Dow Jones and Nikkei stock indexes, where we test the existence and nature of rank dependence, finding usual patterns. We also find violations of rank dependence.

On Myopic Stability Concepts for Hedonic Games

We present a unified look at myopic stability concepts for hedonic games, and discuss the status of the existence problems of stable coalition structures. In particular, we show that contractual strictly core stable coalition structures always exist, and present a sufficient condition for the existence of contractually Nash stable coalition structures on the class of separable games. We gratefully acknowledge financial support from the Alexander von Humboldt Foundation (D. Dimitrov)“by “D. Dimitrov gratefully acknowledges financial support from the Alexander von Humboldt Foundation.     

Whom should we believe? Aggregation of heterogeneous beliefs

We examine the collective risk attitude of a group with heterogeneous beliefs. We prove that the wealth-dependent probability distribution used by the representative agent is biased in favor of the beliefs of the more risk tolerant consumers. Moreover, increasing disagreement on the state probability raises the state probability of the representative agent. It implies that when most disagreements are concentrated in the tails of the distribution, the perceived collective risk is magnified. This can help to solve the equity premium puzzle. We show that the trade volume and the equity premium are positively correlated.

Environmental disasters as risk regulation catalysts? The role of Bhopal,Chernobyl, Exxon Valdez,Love Canal,and Three Mile Island in shaping U.S. environmental law

Unexpected events such as environmental catastrophes capture wide public attention. Soon after five major shocks—Three Mile Island, Love Canal, Bhopal, Chernobyl, and the Exxon Valdez oil spill—Congress voted on new risk regulation. This paper conducts an event study to test whether individual congressional representatives were “shocked” by these environmental disasters into increasing their probability of voting in favor of risk legislation. On average, representatives were less likely to vote in favor of bills tied to these five events. Significant heterogeneity in representatives’ responses to these shocks is documented. Liberal Northeast representatives were most likely to increase their pro-environment voting in the aftermath of these shocks.