Estimation in a truncated bivariate poisson distribution using the EM algorithm

An EM algorithm (Dempster et al., 1977) is derived for the estimation of parameters of the truncated bivariate Poisson distribution with zeros rnissing from both margins. The observed inforrnation matrix is obtained and a numerical exarnple is given where the convergence of the EM algorithm is accelerated by the methods of Louis (1982) and conjugate gradients (Jamshidian antl Jennrich, 1993).     

INCENTIVES FOR DISHONESTY: AN EXPERIMENTAL STUDY WITH INTERNAL AUDITORS

We conduct an experiment with professional internal auditors and evaluate their performance and objectivity, measured as the extent to which they truthfully report the performance of other participants in a real-effort task. In line with our hypotheses, we find that incentive-based compensation increases dishonest behavior: competitive incentives lead to under-reporting of other participants' performance, while collective incentives lead to over-reporting of performance. We replicate these results with a student sample. In addition, we find that moving from an environment with objective performance evaluation toward a peer evaluation scheme reduces performance among internal auditors, but not among students.(JEL C93, M42, M52)     

Conditional even point estimation for bivariate discrete distributions

This paper presents a simple procedure for estimating the parameters of bivariate discrete distributions. The procedure uses the marginal means and certain observed frequencies in one or more conditional distributions. The bivariate Poisson and Negative Binomial distributions are used as illustrative examples, Parameter estimators are derived and asymptotic efficiencies are examined for various parameter values.     

Texas college students' opinions of no-smoking policies, secondhand smoke, and smoking in public places

Abstract. The authors examined college student opinions of no-smoking policies, secondhand smoke, and smoking in public places. A convenience sample of 1,188 (66.4% female; 26.9% White, 64.1% Black, and 9.0% Hispanic) students attending 5 Texas colleges volunteered to complete a 60-item anonymous survey on tobacco attitudes and behaviors. Results of our study showed that women, Black students, and nonsmoking students reported the most favorable attitudes toward no smoking. Male students, white students, and students who smoked in the past 30 days (current smokers) reported the least favorable attitudes. The lowest level of agreement by all subgroups was provided for prohibiting smoking everywhere on campus (inside and outside of buildings). Implications for tobacco control on college campuses are discussed.     

Supply chain reconfiguration opportunities arising from additive manufacturing technologies in the digital era

Abstract

The aim of this study is to explore the impact of additive manufacturing (AM) technologies on the configuration opportunities of supply chains (SCs) within the digital manufacturing era. To this effect, we first conduct a critical taxonomy of existing research efforts and then propose an integrated decision-making process for the design and management of SCs defined by digital manufacturing technologies. Following, we provide an integrated framework for future SC reconfiguration opportunities arising from the adoption of AM on a supply network setting. Our analysis demonstrates the significant ramifications of AM techniques on SC configuration and sustainability performance as opposed to conventional value networks; however, existing research is evidently limited due to scope related challenges and the inherent complexity at the manufacturing echelon of the respective supply networks.     

Cigarette smoking and cessation among trade or technical school students in Texas

Although students enrolled in trade or technical colleges are at an elevated risk for tobacco use, virtually no information exists regarding their smoking behaviors. OBJECTIVE AND PARTICIPANTS: In the present study, the authors examined (1) the prevalence of smoking and quitting among 617 students in 2 trade or technical colleges in East Texas and (2) on-campus media exposure to antitobacco messages. METHODS: Students voluntary completed the 42-item Texas Trade and Technical School Tobacco Survey during a required introductory-level class. RESULTS: Of the participating students, 34% reported past-30-day smoking (current smoking). Of current smokers, 74% reported a previous quit attempt and 64% wanted to quit before graduation. Although most current smokers expressed a desire to quit smoking, the antitobacco message they were least likely to see on campus was that regarding how to quit. Current smokers cited their own health as the most likely reason to quit smoking, and most reported wanting to quit on their own, without the use of resources. However, of the 9 listed resources, students were most likely to report the possible use of medication. CONCLUSIONS: Given that most smoking students desire to quit smoking--and that they are enrolled in trade or technical schools for an extended period of time--additional research should examine how successful interventions can be delivered at the trade or technical school itself.     

College students' perceptions of risk and addictiveness of e-cigarettes and cigarettes

Background: As conventional cigarette use is declining, electronic cigarette (“e-cigarette”) use is rising and is especially high among college students. Few studies examine dual use of e-cigarettes and cigarettes among this population. This study explores the relationship between dual and exclusive e-cigarette / cigarette use and perceptions of harm and addictiveness of both products. Methods: This is a cross-sectional analysis of data from students attending 24 colleges in Texas (n=5,482). Multinomial logistic regression was employed to test the association between current e-cigarette / cigarette use and perceived harm and addictiveness of both products. Three tobacco groups were included: cigarette only users, e-cigarette only users, and dual users. Results: Dual users reported lower perceived harm of e-cigarettes most consistently (p<0.001, all comparisons). Perceived harm of cigarettes was significantly lower among cigarette only and dual users only, compared to non-users (p<0.001, all comparisons). Compared to non-users, all three groups reported significantly lower perceived addictiveness of e-cigarettes (p<0.001, all comparisons). The same finding was observed for perceived addictiveness of cigarettes, though findings were less consistent for the e-cigarette only group (p<0.02, all comparisons except one). Conclusion: Findings demonstrate that among college students, perceptions of harm and addictiveness of e-cigarettes are lower than those for conventional cigarettes. For both products, perceptions of harm and addictiveness were lower among exclusive and dual users, compared to non-users.     

THE OPTIMAL ALLOCATION OF PRIZES IN TOURNAMENTS OF HETEROGENEOUS AGENTS

Tournaments are widely used in organizations, explicitly or implicitly, to reward the best‐performing employees, for example, by promotion or bonuses, and/or to penalize the worst‐performing employees, for example, by demotion, withholding bonuses, or unfavorable job assignments. These incentive schemes can be interpreted as various prize allocations based on the employees' relative performance. While the optimal prize allocation in tournaments of symmetric agents is relatively well understood, little is known about the impact of the allocation of prizes on the effectiveness of tournament incentive schemes for heterogeneous agents. We show that while multiple prize allocation rules are equivalent when agents are symmetric in their ability, the equivalence is broken in the presence of heterogeneity. Under a wide range of conditions, loser‐prize tournaments, that is, tournaments that award a low prize to relatively few bottom performers, are optimal for the firm. The reason is that low‐ability agents are discouraged less in such tournaments, as compared to winner‐prize tournaments awarding a high prize to few top performers, and hence can be compensated less to meet their participation constraints. (JEL M52, J33, J24)