高层管理团队的异质性与企业绩效的实证研究

研究了我国企业所处行业的动态性对高层管理团队异质性与企业绩效关系的影响。采用我国深、沪两市356家上市公司2001~2002年的数据进行了实证分析。结果表明,在我国企业中,高层管理团队职业经验异质性、年龄异质性与行业动态性的交互作用在各自对企业绩效的影响中起了负向的调节作用,进而对这种结果进行了具体的分析和讨论,并提出了未来研究的展望。     

Structural holes and managerial performance: Identifying the underlying mechanisms

Structural holes theory suggests a variety of possible explanations for the empirically observed relationship between structural holes and individual managerial performance. However, little has been done to disentangle one mechanism from another. This paper empirically tests a mediated moderation model that distinguishes between the five different theoretical mechanisms: autonomy, competition, information brokering, opportunity recognition and innovativeness. The findings suggest that of these five theoretical causal motors, innovativeness plays a key role in linking network structure and network content to performance.     

Semiparametric Analysis of Network Formation

ABSTRACT

We consider a statistical model for directed network formation that features both node-specific parameters that capture degree heterogeneity and common parameters that reflect homophily among nodes. The goal is to perform statistical inference on the homophily parameters while treating the node-specific parameters as fixed effects. Jointly estimating all parameters leads to incidental-parameter bias and incorrect inference. As an alternative, we develop an approach based on a sufficient statistic that separates inference on the homophily parameters from estimation of the fixed effects. The estimator is easy to compute and can be applied to both dense and sparse networks, and is shown to have desirable asymptotic properties under sequences of growing networks. We illustrate the improvements of this estimator over maximum likelihood and bias-corrected estimation in a series of numerical experiments. The technique is applied to explain the import and export patterns in a dense network of countries and to estimate a more sparse advice network among attorneys in a corporate law firm.     

‘Show me the money and the party!’ – variation in Facebook and Twitter adoption by politicians

Our study explores the adoption of Facebook and Twitter by candidates in the 2013 German Federal elections. Utilizing data from the German Longitudinal Election Study candidate survey fused with data gathered on the Twitter and Facebook use of candidates, we draw a clear distinction between Facebook and Twitter. We show that adoption of both channels is primarily driven by two factors: party and money. But the impact of each plays out differently for Facebook and Twitter. While the influence of money is homogenous for Facebook and Twitter with the more resources candidates have, the more likely they are to adopt, the effect is stronger for Facebook. Conversely, a party’s impact on adoption is heterogeneous across channels, a pattern we suggest is driven by the different audiences Facebook and Twitter attract. We also find candidates’ personality traits only correlate with Twitter adoption, but their impact is minimal. Our findings demonstrate that social media adoption by politicians is far from homogenous, and that there is a need to differentiate social media channels from one another when exploring motivations for their use.     

Multistate life‐tables and regression models

A survey is given of the use of modern statistical techniques in event history analysis, and in particular in the study of multi‐state life‐tables in demography. Emphasis is placed on the interplay between partial likelihood and nonparametric maximum likelihood based methods, a) when analysing semi‐Markov models or models with repeated spells, and b) in frailty models for inobservable heterogeneity.     

ROBUSTNESS OF PROCEDURES FOR THE BEHRENS-FISHER PROBLEMS: EXTENSION TO BIVARIATE NORMAL MIXTURES

In the applied sciences, it is often important to be able to compare the mean values of two populations. However, testing a hypothesis can be complex, if the two populations are heteroscedastic and exhibit non-normality in the data. This paper reviews currently available strategies for the multivariate Behrens-Fisher problem. It then carries out Monte Carlo comparisons of selected procedures to assess their robustness when applied to data from normal mixture distributions. The overall conclusion is that Johansen's procedure appears to work best for small sample data both in terms of empirical power and significance level. Johansen's procedure works reasonably well even with mixture data. The simulation also provides researchers with specific guidelines to follow at the early designing and planning stages of the investigation.     

论类型学的定义与范畴

探讨类型学的实质及其研究范围,以寻求真正适合国内教学与研究实践的类型学理论极具意义。文章梳理了国内比较文学教材对类型学的定义,发现大多只强调类同性的研究,而忽视对异质性的关注。在这一理论的指导下,中国大多数类型学研究只强调求同。这与俄苏的历史类型学求同存异的学术旨趣是不同的。曹顺庆教授提倡类型学的异质研究,既是对俄苏历史类型学研究思路的回归,更偏重于寻求不同文化的异质性。类型学异质研究是第三世界国家在跨文明语境下开展类型学类同研究陷入困境时的一种努力,这对构建民族自信心,维护世界多元文化和谐的生态环境有积极的意义。本文认为真正完整而有可操作性的类型学研究应该包括两个步骤：先进行类同研究,然后再进行异质研究。     

Acute Middle Ear Infection in Small Children: A Bayesian Analysis Using Multiple Time Scales

The study is based on a sample of 965 children living in Oulu region (Finland), who were monitored for acute middle ear infections from birth to the age of two years. We introduce a nonparametrically defined intensity model for ear infections, which involves both fixed and time dependent covariates, such as calendar time, current age, length of breast-feeding time until present, or current type of day care. Unmeasured heterogeneity, which manifests itself in frequent infections in some children and rare in others and which cannot be explained in terms of the known covariates, is modelled by using individual frailty parameters. A Bayesian approach is proposed to solve the inferential problem. The numerical work is carried out by Monte Carlo integration (Metropolis-Hastings algorithm).     

Model-based measurement of latent risk in time series with applications

Summary.  Risk is at the centre of many policy decisions in companies, governments and other institutions. The risk of road fatalities concerns local governments in planning countermeasures, the risk and severity of counterparty default concerns bank risk managers daily and the risk of infection has actuarial and epidemiological consequences. However, risk cannot be observed directly and it usually varies over time. We introduce a general multivariate time series model for the analysis of risk based on latent processes for the exposure to an event, the risk of that event occurring and the severity of the event. Linear state space methods can be used for the statistical treatment of the model. The new framework is illustrated for time series of insurance claims, credit card purchases and road safety. It is shown that the general methodology can be effectively used in the assessment of risk.     

The consequences of unobserved heterogeneity in a sequential logit model

Cameron and Heckman (1998) established that a sequential logit model is more sensitive than many other models to the possible biasing influence of unobserved heterogeneity. This article proposes a method which allows researchers to find out how large this potential problem is for their data, their model, and their hypothesis of interest. This is done by proposing a set of scenarios for this unobserved heterogeneity, and showing how to estimate the effects of interest given these scenarios. The set of results from these scenarios give an indication of how sensitive the results are to assumptions regarding unobserved heterogeneity. This sensitivity analysis has been applied to a study of educational attainment in the Netherlands, and it showed that that the finding that the effect of father's education declined over transitions is quite sensitive to the assumptions made about unobserved heterogeneity, but that the finding that the effect of father's education declined over birth cohorts is more robust than is often feared.