Investment in Shared Suppliers: Effect of Learning,Spillover, and Competition

We investigate the optimal strategies for firms to invest in their suppliers when the benefits of such investments can spillover to other firms who also source from the same suppliers. We consider two Bayesian firms that can invest in improving the quality of their shared supplier; the firms do not have complete information on the true quality of the supplier, but they update their beliefs based on the supplier's performance. We formulate the problem as an investment game and obtain Markov perfect equilibria characterized by the investment thresholds of both firms. The equilibrium investment strategies of the two firms are characterized by a region of preemption and a region of war of attrition. We also examine how the interplay between spillover, competition, and returns from the investment at shared suppliers affect the investment threshold and the time to the leader's investment, and identify the conditions under which competition delays or hastens the first investment in a shared supplier.     

Factors Associated With Substance Use Disorders Among Traumatized Homeless Youth

This study aimed to identify homeless youths’ lifestyle and trauma-related risk factors as well as protective factors associated with alcohol use disorder or no disorder and drug use disorder or no disorder. Youth receiving homeless services in Denver (n = 201), Austin (n = 200), and Los Angeles (n = 200; N = 601) completed quantitative interviews assessing demographic information, alcohol and drug use, homeless lifestyle risk factors, trauma-related risk factors, and protective factors. Findings showed differences in trauma-related risk factors between alcohol and drug use disorders, but not homeless lifestyle risks. Protective factors predicted substance use disorders beyond risk factors. Understanding trauma-related risk and protective factors associated with substance use disorders could improve interventions.     

Complex Interrelations of Trait Vulnerabilities in Mothers and their Infants

Despite the developmental and clinical relevance of this area of inquiry, no studies have examined the interrelations of trait vulnerabilities in the affective, behavioral, and interpersonal domains between mothers and their infants. Thus, this study examined the interrelations of three trait vulnerabilities (i.e., negative affective intensity, impulsivity, and insecure attachment) between mothers and their 12‐ to 23‐month‐old infants, focusing in particular on the unique and interactive influence of these maternal trait vulnerabilities on the expression of and precursors to these traits in their infants. Mother–infant dyads (N = 101) completed several laboratory procedures, and mothers reported on their own and their infants' expressions of the trait vulnerabilities of interest. Findings from this study provide preliminary evidence for intergenerational relations between these traits and suggest that it is the confluence of trait vulnerabilities in mothers that relates to the early expression of some of these traits in infants.     

刑法上的自救行为

韩国刑法典中,作为违法性阻却事由之一明确规定有"自救行为"。韩国刑法中的"自救行为"指依据法定程序不可能保全请求权时,为避免其请求权的实行不能或显著的实行困难而实施的行为,其具有在紧急状况中私人代行国家权力的行为性质。韩国刑法"自救行为"的成立需要具备如下条件:一是自救行为状况;二是自救意思;三是相当理由。一旦成立自救行为,即使发生符合构成要件的结果,也将阻却违法性而不成立犯罪。     

Intergenerational Exchanges of Middle‐Aged Adults With Their Parents and Parents‐In‐Law in Korea

The authors investigated patterns of support exchanges between Korean adult children and their parents and parents‐in‐law, gender differences in these patterns, and implications of children's marital quality for exchange patterns. Data were from a nationally representative sample of married adults (N = 920, age 30–59 years) with at least 1 living parent and 1 living parent‐in‐law. Latent class analysis was applied to 12 indicators of exchanges (financial, instrumental, emotional support given to and received from parents and parents‐in‐law). Five classes of exchanges were identified, 3 showing balanced patterns of exchanges with parents and parents‐in‐law across three types of support and 2 classes with unbalanced patterns (e.g., giving instrumental and financial but not emotional support). The findings revealed variability in intergenerational exchange patterns, with a mix of patrilineal traditional and balanced patterns. Significant associations of exchange patterns with adult children's marital quality suggest the importance of balanced exchanges with parents for marriage.     

ON THE EXTERNAL VALIDITY OF LABORATORY TAX COMPLIANCE EXPERIMENTS

An essential issue for laboratory experiments to inform policy debates is the “external validity” of the experimental results; that is, does behavior in the laboratory apply to behavior that occurs in the naturally occurring world? We examine this issue of external validity in the specific context of laboratory experiments on tax compliance, using two different types of evidence. We find that the behavioral patterns of subjects in the laboratory conform to those of individuals making a similar decision in naturally occurring settings. We also find that the behavioral responses of students are largely the same as those of nonstudents in identical experiments (JEL C9, H0, H3)     

Unit Root Tests in the Presence of Multi-Variance Break and Level Shifts That Have Power Against the Piecewise Stationary Alternative

Structural breaks in the level as well as in the volatility have often been exhibited in economic time series. In this paper, we propose new unit root tests when a time series has multiple shifts in its level and the corresponding volatility. The proposed tests are Lagrangian multiplier type tests based on the residual's marginal likelihood which is free from the nuisance mean parameters. The limiting null distributions of the proposed tests are the χ²distributions, and are affected not by the size and the location of breaks but only by the number of breaks.

We set the structural breaks under both the null and the alternative hypotheses to relieve a possible vagueness in interpreting test results in empirical work. The null hypothesis implies a unit root process with level shifts and the alternative connotes a stationary process with level shifts. The Monte Carlo simulation shows that our tests are locally more powerful than the OLSE-based tests, and that the powers of our tests, in a fixed time span, remain stable regardless the number of breaks. In our application, we employ the data which are analyzed by Perron (1990), and some results differ from those of Perron's (1990).     

合理性与合法性:现代化的两块基石

在实现经济现代化方面,起至关重要作用的两大决定性因素就是市场和企业组织。但是,市场和企业的正常运作却离不开公共行政的相对独立及其作用。实际上,现代市场、现代企业组织、相对独立于政治的公共行政这三者之间,不仅存在着产生和发展上的共时性,而且在相互关系上也存在着内在的和必然的逻辑联系,从而推动了现代经济的迅速发展。这种内在联系来自三者的共同基础,这就是合理性和合法性。因此,合理性和合法性是现代化的逻辑基础,也可以把合理性和合法性看成是衡量现代化程度的两项主要尺度。     

Supplementing a survey with respondent Twitter data to measure e-cigarette information exposure

ABSTRACT

Social media data are increasingly used by researchers to gain insights on individuals’ behaviors and opinions. Platforms like Twitter provide access to individuals’ postings, networks of friends and followers, and the content to which they are exposed. This article presents the methods and results of an exploratory study to supplement survey data with respondents’ Twitter postings, networks of Twitter friends and followers, and information to which they were exposed about e-cigarettes. Twitter use is important to consider in e-cigarette research and other topics influenced by online information sharing and exposure. Further, Twitter metadata provide direct measures of user’s friends and followers as opposed to survey self-reports. We find that Twitter metadata provide similar information to survey questions on Twitter network size without inducing recall error or other measurement issues. Using sentiment coding and machine learning methods, we find Twitter can elucidate on topics difficult to measure via surveys such as online expressed opinions and network composition. We present and discuss models predicting whether respondents’ tweet positively about e-cigarettes using survey and Twitter data, finding the combined data to provide broader measures than either source alone.