The Time Series and Cross‐Section Asymptotics of Dynamic Panel Data Estimators

In this paper we derive the asymptotic properties of within groups (WG), GMM, and LIML estimators for an autoregressive model with random effects when both T and N tend to infinity. GMM and LIML are consistent and asymptotically equivalent to the WG estimator. When T/N→ 0 the fixed T results for GMM and LIML remain valid, but WG, although consistent, has an asymptotic bias in its asymptotic distribution. When T/N tends to a positive constant, the WG, GMM, and LIML estimators exhibit negative asymptotic biases of order 1/T, 1/N, and 1/(2N−T), respectively. In addition, the crude GMM estimator that neglects the autocorrelation in first differenced errors is inconsistent as T/N→c>0, despite being consistent for fixed T. Finally, we discuss the properties of a random effects pseudo MLE with unrestricted initial conditions when both T and N tend to infinity.     

Cross‐Section Regression with Common Shocks

This paper considers regression models for cross‐section data that exhibit cross‐section dependence due to common shocks, such as macroeconomic shocks. The paper analyzes the properties of least squares (LS) estimators in this context. The results of the paper allow for any form of cross‐section dependence and heterogeneity across population units. The probability limits of the LS estimators are determined, and necessary and sufficient conditions are given for consistency. The asymptotic distributions of the estimators are found to be mixed normal after recentering and scaling. The t, Wald, and F statistics are found to have asymptotic standard normal, χ², and scaled χ² distributions, respectively, under the null hypothesis when the conditions required for consistency of the parameter under test hold. However, the absolute values of t, Wald, and F statistics are found to diverge to infinity under the null hypothesis when these conditions fail. Confidence intervals exhibit similarly dichotomous behavior. Hence, common shocks are found to be innocuous in some circumstances, but quite problematic in others. Models with factor structures for errors and regressors are considered. Using the general results, conditions are determined under which consistency of the LS estimators holds and fails in models with factor structures. The results are extended to cover heterogeneous and functional factor structures in which common factors have different impacts on different population units.     

General Probability‐Time Tradeoff and Intertemporal Risk‐Value Model

This article proposes an intertemporal risk‐value (IRV) model that integrates probability‐time tradeoff, time‐value tradeoff, and risk‐value tradeoff into one unified framework. We obtain a general probability‐time tradeoff, which yields a formal representation form to reflect the psychological distance of a decisionmaker in evaluating a temporal lottery. This intuition of probability‐time tradeoff is supported by robust empirical findings as well as by psychological theory. Through an explicit formalization of probability‐time tradeoff, an IRV model taking into account three fundamental dimensions, namely, value, probability, and time, is established. The object of evaluation in our framework is a complex lottery. We also give some insights into the structure of the IRV model using a wildcatter problem.     

A Dynamic Model for the Cross‐sectional Distribution of Unemployment Rates

This paper proposes a model to describe the continuous time‐evolution of density of the cross‐sectional distribution of unemployment rates. The model is founded on the theory of analytical diffusion processes. The steady‐state distribution as well as the dynamic behaviour of the model are analytically derived. Parameters in the resulting analytical expressions are then fitted to US regional data. The empirical portion of the paper illustrates the usefulness of modeling the temporal evolution of the cross‐sectional distribution of unemployment rate, rather than simply attending to equilibrium implications of the process.     

Offshoring and Cross‐Border Interorganizational Relationships: A Justice Model*

In this article, we develop an interorganizational justice model to explain cross‐border interorganizational relationships. The model contends that cultural distance (construed as the cultural differences between offshoring partners) would influence behavioral uncertainty and the boundary spanners' perceptions of justice. Specifically, the model predicts that high levels of behavioral uncertainty are likely to reduce relational commitment, whereas low levels of behavioral uncertainty are likely to enhance relational commitment. However, boundary spanners' perceptions of distributive, procedural, and interactional justice would mitigate the negative impact of behavioral uncertainty on relational commitment. The model also predicts that culturally similar boundary spanners would be more likely to share similar perceptions of distributive, procedural, and interactional justice than culturally dissimilar boundary spanners. This model has implications for further theoretical discussion and empirical research as well as management practice. Managers could use the interorganizational justice model to assess shared perceptions of justice among boundary spanners and develop transcultural justice competencies.     

Time‐Varying Risk Premium in Large Cross‐Sectional Equity Data Sets

We develop an econometric methodology to infer the path of risk premia from a large unbalanced panel of individual stock returns. We estimate the time‐varying risk premia implied by conditional linear asset pricing models where the conditioning includes both instruments common to all assets and asset‐specific instruments. The estimator uses simple weighted two‐pass cross‐sectional regressions, and we show its consistency and asymptotic normality under increasing cross‐sectional and time series dimensions. We address consistent estimation of the asymptotic variance by hard thresholding, and testing for asset pricing restrictions induced by the no‐arbitrage assumption. We derive the restrictions given by a continuum of assets in a multi‐period economy under an approximate factor structure robust to asset repackaging. The empirical analysis on returns for about ten thousand U.S. stocks from July 1964 to December 2009 shows that risk premia are large and volatile in crisis periods. They exhibit large positive and negative strays from time‐invariant estimates, follow the macroeconomic cycles, and do not match risk premia estimates on standard sets of portfolios. The asset pricing restrictions are rejected for a conditional four‐factor model capturing market, size, value, and momentum effects.     

Unemployment and Retirement in a Model with Age‐specific Heterogeneity

This paper presents a model where young and old workers compete for one type of jobs in the presence of retirement opportunity. Within this framework, we show that increased retirement opportunities (such as a decrease of the retirement age) has most of the time a depressing impact on the unemployment rate. Indeed the number of vacancies posted by firms is influenced by the probability that an old worker is going into retirement. We show that the degree to which younger workers are influenced by retirement of older workers depends on the relative productivity of young and older workers. It is only when older workers are much more productive than young workers that retirement may benefit to unemployment.     

Fractional Poisson—A Simple Dose‐Response Model for Human Norovirus

This study utilizes old and new Norovirus (NoV) human challenge data to model the dose‐response relationship for human NoV infection. The combined data set is used to update estimates from a previously published beta‐Poisson dose‐response model that includes parameters for virus aggregation and for a beta‐distribution that describes variable susceptibility among hosts. The quality of the beta‐Poisson model is examined and a simpler model is proposed. The new model (fractional Poisson) characterizes hosts as either perfectly susceptible or perfectly immune, requiring a single parameter (the fraction of perfectly susceptible hosts) in place of the two‐parameter beta‐distribution. A second parameter is included to account for virus aggregation in the same fashion as it is added to the beta‐Poisson model. Infection probability is simply the product of the probability of nonzero exposure (at least one virus or aggregate is ingested) and the fraction of susceptible hosts. The model is computationally simple and appears to be well suited to the data from the NoV human challenge studies. The model's deviance is similar to that of the beta‐Poisson, but with one parameter, rather than two. As a result, the Akaike information criterion favors the fractional Poisson over the beta‐Poisson model. At low, environmentally relevant exposure levels (<100), estimation error is small for the fractional Poisson model; however, caution is advised because no subjects were challenged at such a low dose. New low‐dose data would be of great value to further clarify the NoV dose‐response relationship and to support improved risk assessment for environmentally relevant exposures.     

Promotability of Host‐Country Nationals: A Cross‐Cultural Study

Drawing on person–environment fit and national identity theory, the article proposes that person–national culture fit is likely to influence the promotability of host‐country nationals in multinational firms. Focusing on fit with upward influence tactics, it suggests that the parent company's national culture influences managerial expectations of host‐country nationals in foreign subsidiaries. It argues that host‐country managers who demonstrate upward influence tactics that are culturally appropriate to the parent company's national culture will be more promotable than those who do not. Higher‐level supervisors were asked to assess the promotability of two direct subordinates, who were independently surveyed about the upward influence tactics they used. The study contrasted ingratiation, exchange of benefits and coalition, and directness influence tactics of host‐country nationals in domestic Ecuadorian firms with American and German multinationals in Ecuador. Compatible with our hypotheses, data from a sample of 79 firms suggest that exchange of benefits and coalition are more likely to be associated with promotability in German than in domestic Ecuadorian firms. In addition, upward‐appeal assertiveness is more likely to be associated with promotability in American than in domestic Ecuadorian firms.     

A Mathematical Model for Pathogen Cross‐Contamination Dynamics during the Postharvest Processing of Leafy Greens

We developed a probabilistic mathematical model for the postharvest processing of leafy greens focusing on Escherichia coli O157:H7 contamination of fresh‐cut romaine lettuce as the case study. Our model can (i) support the investigation of cross‐contamination scenarios, and (ii) evaluate and compare different risk mitigation options. We used an agent‐based modeling framework to predict the pathogen prevalence and levels in bags of fresh‐cut lettuce and quantify spread of E. coli O157:H7 from contaminated lettuce to surface areas of processing equipment. Using an unbalanced factorial design, we were able to propagate combinations of random values assigned to model inputs through different processing steps and ranked statistically significant inputs with respect to their impacts on selected model outputs. Results indicated that whether contamination originated on incoming lettuce heads or on the surface areas of processing equipment, pathogen prevalence among bags of fresh‐cut lettuce and batches was most significantly impacted by the level of free chlorine in the flume tank and frequency of replacing the wash water inside the tank. Pathogen levels in bags of fresh‐cut lettuce were most significantly influenced by the initial levels of contamination on incoming lettuce heads or surface areas of processing equipment. The influence of surface contamination on pathogen prevalence or levels in fresh‐cut bags depended on the location of that surface relative to the flume tank. This study demonstrates that developing a flexible yet mathematically rigorous modeling tool, a “virtual laboratory,” can provide valuable insights into the effectiveness of individual and combined risk mitigation options.     

An Agent‐Based Model for Pathogen Persistence and Cross‐Contamination Dynamics in a Food Facility

We used an agent‐based modeling (ABM) framework and developed a mathematical model to explain the complex dynamics of microbial persistence and spread within a food facility and to aid risk managers in identifying effective mitigation options. The model explicitly considered personal hygiene practices by food handlers as well as their activities and simulated a spatially explicit dynamic system representing complex interaction patterns among food handlers, facility environment, and foods. To demonstrate the utility of the model in a decision‐making context, we created a hypothetical case study and used it to compare different risk mitigation strategies for reducing contamination and spread of Listeria monocytogenes in a food facility. Model results indicated that areas with no direct contact with foods (e.g., loading dock and restroom) can serve as contamination niches and recontaminate areas that have direct contact with food products. Furthermore, food handlers’ behaviors, including, for example, hygiene and sanitation practices, can impact the persistence of microbial contamination in the facility environment and the spread of contamination to prepared foods. Using this case study, we also demonstrated benefits of an ABM framework for addressing food safety in a complex system in which emergent system‐level responses are predicted using a bottom‐up approach that observes individual agents (e.g., food handlers) and their behaviors. Our model can be applied to a wide variety of pathogens, food commodities, and activity patterns to evaluate efficacy of food‐safety management practices and quantify contamination reductions associated with proposed mitigation strategies in food facilities.     

Values and Risk Perceptions: A Cross‐Cultural Examination

This article examines the relationship between values and risk perceptions regarding terror attacks. The participants in the study are university students from Turkey (n = 536) and Israel (n = 298). Schwartz value theory (1992, 1994) is applied to conceptualize and measure values. Cognitive (perceived likelihood and perceived severity) and emotional (fear, helplessness, anger, distress, insecurity, hopelessness, sadness, and anxiety) responses about the potential of (i) being personally exposed to a terror attack, and (ii) a terror attack that may occur in one's country are assessed to measure risk perceptions. Comparison of the two groups suggests that the Turkish participants are significantly more emotional about terror risks than the Israeli respondents. Both groups perceive the risk of a terror attack that may occur in their country more likely than the risk of being personally exposed to a terror attack. No significant differences are found in emotional representations and perceived severity ratings regarding these risks. Results provide support for the existence of a link between values and risk perceptions of terror attacks. In both countries, self‐direction values are negatively related to emotional representations, whereas security values are positively correlated with emotions; hedonism and stimulation values are negatively related to perceived likelihood. Current findings are discussed in relation to previous results, theoretical approaches (the social amplification of risk framework and cultural theory of risk), and practical implications (increasing community support for a course of action, training programs for risk communicators).     

A Cross‐Cultural Study of Perceived Benefit Versus Risk as Mediators in the Trust‐Acceptance Relationship

Several recent studies have identified the significant role social trust in regulatory organizations plays in the public acceptance of various technologies and activities. In a cross‐cultural investigation, the current work explores empirically the relationship between social trust in management authorities and the degree of public acceptability of hazards for individuals residing in either developed or emerging Latin American economies using confirmatory rather than exploratory techniques. Undergraduates in Mexico, Brazil, and Chile and the United States and Spain assessed trust in regulatory authorities, public acceptance, personal knowledge, and the risks and benefits for 23 activities and technological hazards. Four findings were encountered. (i) In Latin American nations trust in regulatory entities was strongly and significantly (directly as well as indirectly) linked with the public's acceptance of any activity or technology. In developed countries trust and acceptability are essentially linked indirectly (through perceived risk and perceived benefit). (ii) Lack of knowledge strengthened the magnitude and statistical significance of the trust‐acceptability relationship in both developed and developing countries. (iii) For high levels of claimed knowledge, the impact on the trust‐acceptability relationship varied depending upon the origin of the sample. (iv) Confirmatory analysis revealed the relative importance of perceived benefit over perceived risk in meditating the trust‐acceptability causal chain.     

Cross‐Cultural Differences in Risk Perceptions of Disasters

Public risk perceptions of mass disasters carry considerable influences, both psychologically and economically, despite their oft‐times imprecise nature. Prior research has identified the presence of an optimistic bias that affects risk perception, but there is a dearth of literature examining how these perceptions differ among cultures—particularly with regard to mass disasters. The present study explores differences among Japanese, Argentinean, and North American mental health workers in their rates of the optimistic bias in risk perceptions as contrasted between natural disasters and terrorist events. The results indicate a significant difference among cultures in levels of perceived risk that do not correspond to actual exposure rates. Japanese groups had the highest risk perceptions for both types of hazards and North Americans and Argentineans had the lowest risk perceptions for terrorism. Additionally, participants across all cultures rated risk to self as lower than risk to others (optimistic bias) across all disaster types. These findings suggest that cultural factors may have a greater influence on risk perception than social exposure, and that the belief that one is more immune to disasters compared to others may be a cross‐cultural phenomenon.     

A Generalized QMRA Beta‐Poisson Dose‐Response Model

Quantitative microbial risk assessment (QMRA) is widely accepted for characterizing the microbial risks associated with food, water, and wastewater. Single‐hit dose‐response models are the most commonly used dose‐response models in QMRA. Denoting as the probability of infection at a given mean dose d, a three‐parameter generalized QMRA beta‐Poisson dose‐response model, , is proposed in which the minimum number of organisms required for causing infection, K_min, is not fixed, but a random variable following a geometric distribution with parameter . The single‐hit beta‐Poisson model, , is a special case of the generalized model with K_min = 1 (which implies ). The generalized beta‐Poisson model is based on a conceptual model with greater detail in the dose‐response mechanism. Since a maximum likelihood solution is not easily available, a likelihood‐free approximate Bayesian computation (ABC) algorithm is employed for parameter estimation. By fitting the generalized model to four experimental data sets from the literature, this study reveals that the posterior median estimates produced fall short of meeting the required condition of = 1 for single‐hit assumption. However, three out of four data sets fitted by the generalized models could not achieve an improvement in goodness of fit. These combined results imply that, at least in some cases, a single‐hit assumption for characterizing the dose‐response process may not be appropriate, but that the more complex models may be difficult to support especially if the sample size is small. The three‐parameter generalized model provides a possibility to investigate the mechanism of a dose‐response process in greater detail than is possible under a single‐hit model.     

The Gatekeeping Function of Trust in Cross‐sector Social Partnerships

Hunger and deprivation, lack of education, sanitation, and health care are only a few pressing issues related to poverty in developing countries. Addressing such complex social issues requires pooling complementary resources of the civil, public, and private sector. Over the last decade, stakeholders tried to cocreate innovative solutions in cross‐sector social partnerships (CSSPs) at the base of the economic pyramid (BoP), but collaboration proved to be very challenging. Practitioners become increasingly frustrated with operational differences, intransparency, and mismatched goals in partnerships. This study unravels the black box of collaboration and delivers empirical insights on trust and power in CSSPs based on social exchange theory. Structural equation modeling (SEM) enables us explore relationships beyond case‐based insights. Our rigorous empirical analysis covers 207 interorganizational relationships and outlines a crucial gatekeeping function of trust in CSSPs. Findings provide strong empirical support for conceptual works calling for an “integrative orientation” in CSSPs. Furthermore, we pinpoint the role of intermediates and draw implications for future research.     

A Single‐Period Assortment Optimization Model

This paper studies a single‐period assortment optimization problem with unequal cost parameters. The consumer choice process is characterized by a Multinomial Logit (MNL) model. When the store traffic is a continuous random variable, we explicitly derive the structure of the optimal assortment. Our approach is to use a comprehensive measure–profit rate to evaluate the profitability of each variant and then determine which product should be offered. We demonstrate that the optimal assortment contains the few items that have the highest profit rate. When the store traffic is discrete, the optimal solution is difficult to obtain. We propose a “profit rate” heuristic, which is inspired by the result for the case of continuous store traffic. In a special case with equal cost parameters and normal demand distribution, the profit rate heuristic is indeed optimal. Using randomly generated data, we test the effectiveness of the heuristic and find that the average percentage error is less than 0.1% and that the hit rate is above 90%. Our research provides managerial insights on assortment planning and accentuates the importance of measuring the profitability of each product when the demand is random and cannibalization among different products exists.     

The Effects of Health Insurance and Self‐Insurance on Retirement Behavior

This paper provides an empirical analysis of the effects of employer‐provided health insurance, Medicare, and Social Security on retirement behavior. Using data from the Health and Retirement Study, we estimate a dynamic programming model of retirement that accounts for both saving and uncertain medical expenses. Our results suggest that Medicare is important for understanding retirement behavior, and that uncertainty and saving are both important for understanding the labor supply responses to Medicare. Half the value placed by a typical worker on his employer‐provided health insurance is the value of reduced medical expense risk. Raising the Medicare eligibility age from 65 to 67 leads individuals to work an additional 0.074 years over ages 60–69. In comparison, eliminating 2 years worth of Social Security benefits increases years of work by 0.076 years.     

Strategies and Tools for Entrepreneurial Resource Access: A Cross‐disciplinary Review and Typology

Given that gaining access to external resources is a critical component of entrepreneurial activity, a great deal of research has been done in an attempt to predict and explain this phenomenon. Unfortunately, this literature is largely scattered across a wide variety of somewhat disconnected research streams, which makes interpreting the insights that have been hitherto gained challenging. In response, the authors identify a sample of 76 relevant articles from the leading management and entrepreneurship journals that examine entrepreneurial access to resources. Using a narrative synthesis approach, they then organize these articles based on the strategies (projective and/or interpersonal) and tools (words, actions, associations and/or intangibles) by which entrepreneurs gain access to resources. Based on this categorization, the authors discuss the major themes in the extant literature and offer suggestions for how to move research on entrepreneurial access forward in the future.     

A Cross‐country Comparison of Attitudes Towards Mothers Working and their Actual Labor Market Experience

In this paper, we use data from the International Social Survey Project to present a cross‐country comparison of attitudes about the labor force participation of mothers. We also estimate earnings functions and probits for full‐time work and examine whether there is a link between attitudes and women’s actual labor market experience across countries. We find that while a woman’s own attitude about work does not directly influence her wage, it does influence the probability that she works full time.