The impact of physical activity on employment

Using cross-sectional data from 25 European countries this study estimates the probability of an individual being employed controlling for his/her participation and frequency of participation in physical activity. Accounting for endogeneity, the regional prevalence of physical activity calculated from the sample is used as an instrument for individual participation suggesting a causal effect of physical activity on employment, especially for males.     

MATERIALS PRICES AND PRODUCTIVITY

There is substantial within‐industry variation in the prices that plants pay for their material inputs. Using plant‐level data from the US Census Bureau, I explore the consequences and sources of this variation in materials prices. For a sample of industries with relatively homogeneous products, the standard deviation of plant‐level productivity would be 7% smaller if all plants faced the same materials prices. Moreover, plant‐level materials prices are persistent, spatially correlated, and positively associated with the probability of exit. The contribution of entry and exit to aggregate productivity growth is smaller for productivity measures that are purged of materials price variation. After documenting these patterns, I discuss three potential sources of materials price variation: geography, differences in suppliers' marginal costs, and within‐supplier markup differences. Together, these variables explain 15% of the variation of materials prices.     

ECOLOGY,TRADE, AND STATES IN PRE‐COLONIAL AFRICA

State capacity matters for growth. I test Bates' explanation of pre‐colonial African states. He argues that trade across ecological boundaries promoted states. I find that African societies in ecologically diverse environments had more centralized states. This is robust to reverse causation, omitted heterogeneity, and alternative interpretations of the link between diversity and states. The result survives including non‐African societies. I test mechanisms connecting trade to states, and find that trade supported class stratification between rulers and ruled. I underscore the importance of ethnic institutions and inform our knowledge of the effects of trade on institutions.     

BUILDING REPUTATION FOR CONTRACT RENEWAL: IMPLICATIONS FOR PERFORMANCE DYNAMICS AND CONTRACT DURATION

We study how career concerns affect the dynamics of incentives in a multi‐period contract, when the agent's productivity is a stochastic function of his past productivity and investment. We show that incentives are stronger and performance is higher when the contract approaches its expiry date. Contrary to common wisdom, long‐term contracts may strengthen reputational effects whereas short‐term contracting may be optimal when investment has persistent, long‐term effects.     

An investigation of project complexity's influence on team communication using Monte Carlo simulation

Research using empirical methods has established a curvilinear relationship between team communication and performance. We conduct virtual experiments to examine team communication and performance when teams work under varying types and levels of project complexity. Data samples, generated using Monte Carlo simulation, are based on the statistical characteristics of empirical data collected from 60 cross-functional project teams that communicated over multiple media (email, phone, and face-to-face) and were completing projects of varying complexity. Regression analysis indicates that project complexity influences the communication-performance relationship. Optimization shows that the communication frequencies at which teams maximize or minimize their performance are dependent upon media used.     

Technology roadmapping for technology-based product-service integration: A case study

Today, since a single product is no longer sufficient to cope with the dynamic market environment, firms are trying to provide the integrated offering of products and services. However, despite the importance and utility of product-service integration, a limited approach has been conducted regarding the planning of the strategic management of integrated offering. To deal with this issue, this paper firstly suggests the concept and typology of technological interface in product-service integration. Based on the technological interface, a generic structure of product-service integrated roadmap is developed. Extended from the generic structure, this paper finally proposes the typological configurations of integrated roadmap according to the technological interface and investigates the usage, characteristics, and roadmapping processes.     

Stakeholders’ roles in virtual project environment: A case study

The rising cost of resources within an organization, increasing capability of information technology, the need to conduct project at different places and availability of competent and inexpensive manpower elsewhere have promoted many companies to adopt project development in a virtual environment. Large scale projects have several full fledged projects conducted by different organizations. Therefore, such projects are called the project of projects (PoPs) here. As PoPs are influenced by stakeholders throughout the project lifecycle, the integration of various projects becomes challenging due to the risks associated with misaligned perceptions, cost, schedule, quality, human resources and communication.This paper describes project context and influencing factors for a PoP's progress in virtual environment and they are explained in terms of two case projects conducted by the author. It is highlighted that communication is an important issue when projects are conducted in virtual environment with different work culture. The communication models and case examples provided here are expected to add knowledge to managing projects in virtual environment.     

THE ECONOMIC EFFECTS OF THE PROTESTANT REFORMATION: TESTING THE WEBER HYPOTHESIS IN THE GERMAN LANDS

Following Max Weber, many theories have hypothesized that Protestantism should have favored economic development. With its religious heterogeneity, the Holy Roman Empire presents an ideal testing ground for this hypothesis. Using population figures of 272 cities in the years 1300–1900, I find no effects of Protestantism on economic growth. The finding is precisely estimated, robust to the inclusion of various controls, and does not depend on data selection or small sample size. Denominational differences in fertility behavior and literacy are unlikely to be major confounding factors. Protestantism has no effect when interacted with other likely determinants of economic development. Instrumental variables estimates, considering the potential endogeneity of religious choice, are similar to the OLS results.     

Ecologically defining the mistreatment of adolescents

Ecologically defined, the problem of adolescent/family conflict for otherwise “normal” families is a reaction to crisis in the life cycle of the family. A family's success in weathering the crisis is indicated by their successful maturation to the next stage of the cycle; we can assume that in such cases the ratio of stress to coping ability was such that the family could integrate that stress. When conflict escalates to abuse and neglect, however, the indication is that stress has outstripped coping ability, and the implication is for stress-reducing intervention quite unlike the standard existing interventions in either the juvenile justice or child welfare systems, which negatively label family members, make them adversaries, fragment their coping capabilities, and even subject them at times to situations worse than those for which they needed help originally. The interventions called for are those that support beleaguered families; that are based on conceptualizations of people as adaptable and capable of solving their own problems if they are given adequate supports.     

Emergency stocks: A theoretical analysis and an illustration for Israel

The paper develops a methodology for designing and evaluating the performance of emergency stocks. The system is required to meet consumers' demands in all emergency situations at a given level of reliability and least possible costs. The model takes into account the various stochastic elements that determine the performance of the system, including the frequency of emergency situations and their expected duration, the pace of replenishing the stocks, the consumption rate in an emergency situation, and the opportunity for stock building prior to the occurance of an emergency on the basis of advance information about the severity of the strategic situation.