A Test of Exogeneity Without Instrumental Variables in Models With Bunching

This paper presents a test of the exogeneity of a single explanatory variable in a multivariate model. It does not require the exogeneity of the other regressors or the existence of instrumental variables. The fundamental maintained assumption is that the model must be continuous in the explanatory variable of interest. This test has power when unobservable confounders are discontinuous with respect to the explanatory variable of interest, and it is particularly suitable for applications in which that variable has bunching points. An application of the test to the problem of estimating the effects of maternal smoking in birth weight shows evidence of remaining endogeneity, even after controlling for the most complete covariate specification in the literature.     

Clinical and behavioral evaluation of pathological gambling in Barcelona,Spain

This paper assesses both the clinical characteristics and gambling behavior of 45 pathological gamblers (40 male, 5 female, average age 41) in a psychiatric hospital in Barcelona, Spain. These pathological gamblers tend to have other addictions and psychiatric disorders in addition to their pathological gambling. Suicidal ideation and attempts were one of the most frequent complications with these patients. Slot and fruit machines were found to be the most preferred form of gambling. Loans and crime were frequently used by the gambler to finance his or her gambling. Nevertheless, the gambler is rarely aggessive, and legal problems resulting from serious crimes are the exception. The profile presentes is similar to that found among pathological gamblers in other countries.     

Modeling wind energy flux by a Birnbaum–Saunders distribution with an unknown shift parameter

In this paper, we discuss a Birnbaum–Saunders distribution with an unknown shift parameter and apply it to wind energy modeling. We describe structural aspects of this distribution including properties, moments, mode and hazard and shape analyses. We also discuss estimation, goodness of fit and diagnostic methods for this distribution. A computational implementation in R language of the obtained results is provided. Finally, we apply such results to two unpublished real wind speed data from Chile, which allows us to show the characteristics of this statistical distribution and to model wind energy flux.     

Robust multivariate control charts based on Birnbaum–Saunders distributions

Multivariate control charts are powerful and simple visual tools for monitoring the quality of a process. This multivariate monitoring is carried out by considering simultaneously several correlated quality characteristics and by determining whether these characteristics are in control or out of control. In this paper, we propose a robust methodology using multivariate quality control charts for subgroups based on generalized Birnbaum–Saunders distributions and an adapted Hotelling statistic. This methodology is constructed for Phases I and II of control charts. We estimate the corresponding parameters with the maximum likelihood method and use parametric bootstrapping to obtain the distribution of the adapted Hotelling statistic. In addition, we consider the Mahalanobis distance to detect multivariate outliers and use it to assess the adequacy of the distributional assumption. A Monte Carlo simulation study is conducted to evaluate the proposed methodology and to compare it with a standard methodology. This study reports the good performance of our methodology. An illustration with real-world air quality data of Santiago, Chile, is provided. This illustration shows that the methodology is useful for alerting early episodes of extreme air pollution, thus preventing adverse effects on human health.     

The relative effect of unionization and interjurisdictional competition on municipal wages

This study analyzes the effect on municipal employee wages of interjurisdictional competition in municipal service markets. The impact of market conditions are analyzed utilizing a bureaucracy model of local governmental decision making. The study develops hypotheses concerning the degree of competition in this market, constructs empirical measures of competition, and investigates the relationship between competition and wage levels for three categories of municipal workers. The empirical results suggest that local market conditions may be as important a determinant of local wages as local labor market conditions, including union membership. Also, the wage effect of unionization appears to be greater in less competitive local government environments. Financial support from the Earhart Foundation is gratefully acknowledged. We would also like to thank Werner Hirsch, Roger Folsom, and Geoffrey Nunn for helpful comments.     

Voluntary childlessness in a society reluctant to change

Voluntary childlessness constitutes a social and generational rupture from tradition and culture, with significant effects on the reproduction of the so-called life and family cycle. This study aims at understanding the reasons why people decide to remain childless and the social pressures that this decision generates. A qualitative phenomenological study was conducted on the emerging decision of non-motherhood and non-fatherhood based on semi-structured interviews with 56 people who autonomously made the decision to opt out of parenthood. This paper underscores the multiple biographical situations involved in the decision, in addition to the concerns about personal development and future. The current social crisis context serves as a means of justification to lessen social and family pressure. We conclude that people who have made this decision promote a different meaning from that of reproduction as a mechanism of the social order.