Hypothesis testing in log-Birnbaum-Saunders regressions

The log-Birnbaum-Saunders regression model introduced by Rieck and Nedelman (1991 Rieck, J. R., Nedelman, J. R. (1991). A log-linear model for the Birnbaum-Saunders distribution. Technometrics 33:51–60. [Google Scholar]) is useful for modeling lifetimes of materials and equipments subject to different conditions. Our goal in this article is twofold. First, we numerically evaluate the finite sample performances of the likelihood ratio, score and Wald tests in the log-Birnbaum-Saunders regression model. Second, we introduce a RESET-like misspecification test for that model. The null hypothesis is that the model is correctly specified which is tested against the alternative hypothesis of model misspecification. The power of the test is evaluated using Monte Carlo simulations. Bootstrap-based inference is also considered. An empirical application is presented and discussed.     

The role of population size in the determination and prediction of population forecast errors: An evaluation using conifidence intervals for subcounty areas

Producers of population forecasts acknowledge the uncertainty inherent in trying to predict the future and should warn about the likely error of their forecasts. Confidence intervals represent one way of quantifying population forecast error. Most of the work in this area relates to national forecasts; although, confidence intervals have been developed for state and county forecasts. A few studies have examined subcounty forecast error, however, they only measured point estimates of error. This paper describes a technique for making subcounty population forecasts and for generating confidence intervals around their forecast error. It also develops statistical equations for calculating point estimates and confidence intervals for areas with different population sizes. A non-linear, inverse relationship between population size and forecast accuracy was found and we demonstrate the ability to accurately predict average forecast error and confidence intervals based on this relationship.     

Orphans and schooling in africa: a longitudinal analysis

AIDS deaths could have a major impact on economic development by affecting the human capital accumulation of the next generation. We estimate the impact of parent death on primary school participation using an unusual five-year panel data set of over 20,000 Kenyan children. There is a substantial decrease in school participation following a parent death and a smaller drop before the death (presumably due to pre-death morbidity). Estimated impacts are smaller in specifications without individual fixed effects, suggesting that estimates based on cross-sectional data are biased toward zero. Effects are largest for children whose mothers died and, in a novel finding, for those with low baseline academic performance.     

Ownership concentration,contestability, family firms,and capital structure

This study analyses the distribution of power among the several blockholders of a firm and the identity of those blockholders as a determinant of firm leverage. Using a sample of 694 firms from 12 Western European countries, our results support a negative relationship between ownership concentration in the hands of the main blockholder and firm leverage. Moreover, we detect that the presence of a second and third large shareholder (beyond the first blockholder) has a significant positive effect on the leverage ratio. In addition, the results show that contestability in family firms plays a more relevant role. Finally, we show that family firms do have significant impact on firm leverage level, and this impact varies depending on the legal framework and institutional environment. In our main sample the results show family firms negatively affect market leverage, supporting the theory that family firms are more averse to an increase in the debt level due to the risk of bankruptcy and financial distress as a result of having an under-diversified portfolio. In contrast, the opposite effect is found in the sample that excludes the United Kingdom. This last result cannot be explained by agency theory, given that family businesses are those that suffer less from Type I agency problems. This result suggests either some difficulty in financing their investments by issuing new equity or the need to use debt as a signal of the quality of its investments. Our results prove to be stable against a battery of robustness tests.     

AN ANALYSIS OF PERSONAL CHARACTERISTICS RELATED TO PROFESSIONAL STAFF TURNOVER IN PUBLIC ACCOUNTING FIRMS1

A sample of graduate and undergraduate degree holders in accounting are being studied during the first five years of their public accounting careers. Data on the biographical characteristics, vocational interests, and personality factors are analyzed in this study to discover if different profiles exist for those who remain with their firm of original employment in public accounting following graduation and those who find new positions. A number of significant differences were found. The findings should be of benefit to educators and representatives from the accounting profession because of their mutual concern with recruiting, staff development and retention, and academic preparation and career counseling.     

Sexuality and digital Space

Since the Internet's inception, sociologists have sought to understand the role digital spaces play in mediating communication, interaction, and its impact on the broader social world. Sociological literature at the intersection of sexuality and digital space presents a key area of inquiry, charting the generative, and sometimes utopian, aspects of sexuality's insertion into the virtual sphere, as well as the problems and drawbacks of this relationship. By drawing on select empirical studies, this article charts three dominant research strands on sexuality and digital space: (a) the influence of digital platforms in sexual selfhood projects; (b) macro‐level trends and micro‐level practices of desire, attraction, and dating online; and (c) the role of digital platforms in sustaining sexual subcultures. I propose additional approaches and lines of inquiry to further develop research in these areas.     

On the three-way equivalence of AUC in credit scoring with tied scores

In credit scoring, it is well known that AUC (the area under curve) can be calculated geometrically, by the probability of a correct ranking of a good and bad pair, and by the Wilcoxon Rank-Sum statistic. This three-way equivalence was first present by Hanley and McNeil in 1982 without considering tied scores and without giving analytical proofs. In this paper, we extend the three-way equivalence to the case with tied scores and provide analytic proofs for the three-way equivalence.     

Civic and Political Participation of Children and Adolescents: A Lifestyle Analysis for Positive Youth Developmental Programs

Social participation plays a key role in predicting positive youth development (PYD). As a previous step of this link, this research examined how children and adolescents' relational lifestyles influenced their participation in political and civic activities. This research provides a multi‐dimensional approach to the study of children's social participation, based on six children's lifestyles factors (i.e. family dialogue, risky behaviours, cultural activities, civic values, family supervision and peer group relationships). Using data from an international survey that included 6130 participants (2198 Spanish, 3932 Italian, Mage = 13.8), this study's results show that relational lifestyles (especially family dialogue and out‐of‐school cultural activities) are positively related to political and civic participation among children and adolescents. On the contrary, some peer group relationships decreased their social participation in those key dimensions for PYD. Limitations of the current study, implications for future policy decisions and applications to children social programs are discussed.     

Cape Verde: Rethinking Diaspora in Development Policy

In today's global economy, small developing countries like Cape Verde have very few options to spur growth and sustain long term socioeconomic development. Small size, poor resource endowment, declining foreign aid, and decreasing opportunities in the world economy have sharply reduced their options for growth and competitiveness. In response, Cape Verde and other small states have been placing increasing focus on migration as a development resource. For a country with a centuries long history of migration and a diaspora estimated to be twice the size of the resident population, harnessing the diaspora is a viable option for Cape Verde. But under what conditions is such an option effective? This article analyses the evolution of the diaspora's economic role, and assesses the conditions that enable or obstruct the diaspora's role as a development resource.